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Stats Test
Study Guide
105
Sports
12/15/2011

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Term
Tourism: Standard error of the slope for this estimated regression equation
Definition
.07917
Term
Tourism: Calculated t-statistic to test whether the regression slope is significant
Definition
3.725
Term
Tourism: p-value associated with this statistic is .006. At the 0.05 level of significance..
Definition
A & C. Reject the Null, Conclude that the number of foreign visitors is significant in explaining tourism revenue
Term
Tourism: How much of the variability in tourism revenue is accounted for by the number of foreign visitors?
Definition
.634.
Term
Tourism: If we were interested in predicting the tourism revenue for a particular country that had 30 million foreign visitors
Definition
We should construct a prediction interval using this equation.
Term
Horseshoe Plot:The residual plot for a linear regression model is shown below. which of the following is true?
Definition
The linear model is no good because of hte curve in the residuals
Term
Below is the plot of residuals versus x values for a regression model. Which assumption appears to be violated?
Definition
Constant variance assumption.
Term
Cordless Electric Shavers: What are the Null and Alternative hypotheses?
Definition
Ho: mean time=400 minutes
Ha: mean time>400 minutes
Term
Cordless Electric Shavers: The correct calculated value of the test statistic is?
Definition
1.201
Term
Cordless electric Shavers:The correct conclusion at the .05 level of significance is..
Definition
Do not reject the null hypothesis
Term
I want to test Ho: p=0.4 vs Ha: P/=0.4 using a test of hypothesis. If i concluded that p is 0.4 when, in fact, the true value of p is not 0.4 then i have made a
Definition
Type 2 error
Term
A local eat-in pizza restaurant wants to investigate the possiblity of starting to deliver pizzas. the owner of the store has determined that home dleivery will be successul only if hte average time spent on a delivery does not exceed 40 minutes. The owner has randomly selected 18 customers and delivered pizzas to their homes in order to test whether the mean delivery time actually exceeds 40 minutes. What assumption is necessary for the test to be valid?
Definition
The population of delivery times must have a normal distribution.
Term
The business college computing center wants to determine the proportion of business students who have laptop computers. If the proportion exceeds 30% then the lab will scale back a proposed enlargement of its facilities. Suppose 200 business students were randomly sampled and 65 have laptops. Which of the following assumptions is necessary for the test to be valid?
Definition
The sample size n satisfies both np0>=15 and nq0>=15
Term
Suppose your company has 3 independent investment plans. Each plan's yearly revenue is normally distributed with mean 5 million dollars and standard deviation 2 million dollars. Each investment is considered a success if the yearly revenue is greater than the cost. What is the probability of getting exactly two successful investments out of these 3 investments
Definition
.4425
Term
A correlation of zero between two quantiative variables means that
Definition
There is no linear association between the two variables
Term
A regression alalysis of company profits and the amount of money the company spent on advertising produced a R^2=.72. Which of these is true.
Definition
72% of the variance in company profit can be accounted for by the model.
Term
Insurance Company: Standard deviation of hte sampling distribution of the sample propportion of policyholders filing claims involving theft or robbery from their homes is
Definition
.015
Term
Insurance Company: The probability that the sample proportion of policyholders filing claims involving theft or robbery from their homes is less than 8% is
Definition
.0918
Term
A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of hte sample mean whenever the sample size is large(over 30) is the
Definition
Central limit theorem.
Term
We have calculated a 95% confidence interval and would like our next confidence interval to have a smaller margin of error without losing any confidence. in order to do this, we can
Definition
Take a larger Sample
Term
Retirement Incentives: The estimated proportion of companies that downsize their workforces by offering early retirement incentives is
Definition
.2697
Term
Retirement Incentives: The 99% confidence interval for the proportion of companies that downsize their workforces by offering early retirement incentives is
Definition
(227,312)
Term
What are the conditions for the interval estimate in question 22 to be valid?
Definition
The 723 companies is a random sample that is representative of the population,np>15 were n is sample size and phat is sample proportion
Term
We have created a 95% confidence interval for mu with the result (10,15). What conclusion will we make if we test Ho: mu=16 versus Ha: mu does not equal 16 at a=.05
Definition
Reject the null hypothesis
Term
Which is true about a 99% confidence interval based on a given sample?
Definition
The interval is wider than a 95% confidence interval would be.
Term
A human resources manager at a large company wants to estimate the proportion of employees that would be interested in reimburesement for college courses. If she wishes to be 95% confident that her estimate is within 5% of the true proportion, how many employees would need to be sampled?
Definition
385 people
Term
An urban planning group is inerested in estimating the difference in mean household income between two neighborhoods. They obtain the following 95% confidence interval: 95% CI for difference: (-5693,-4107) Which of the following is true
Definition
This is a paired design, There is a significant difference in the mean household incomes between the two neighborhoods.
Term
Shape-Up-by Susy: Which of the following statements is true?
Definition
This is a paired design,This is a one-tailed test
Term
Shape-up-Suzy:At the .05 level of significance, the correct conclusion is
Definition
Reject the null hypothesis, Susies claim is supported by sample evidence.
Term
Survey of Investors:The probability that an investor selected at random uses a full service brokerage firm to invest in stocks or trades stocks online is
Definition
66%
Term
Survey of Investors: What is the probability that an investor selected at random neither uses a full service brokerage firm to invest in stocks nor trades online is
Definition
34%
Term
Gender on Job Category:What is the probability that a randomly selcted employees job category is executive/managerial?
Definition
25%
Term
Gender on Job Category:What is the probability that a randomly selected emplyee's job category is executive/ managerial given that she is female?
Definition
12.58%
Term
Which of the following statemnets is true about gender and job category?
Definition
Gender and job category are not independent
Term
Health Insurance Histogram: What is the most appropriate measure to describe the center of these data?
Definition
Median
Term
Health Insurance Histogram: The IQR for these data is
Definition
5.9
Term
A researcher is conducting a study on internet use. He decides to first categorize the population by education level and the nsurvey a slect number from each category. This sampling strategy is called
Definition
Stratified
Term
EPS Boxplot: Which of the following statments is correct:
Definition
The median EPS is higher for retail stocks compared to energy stocks
Term
EPS Box plot: Which of the following statemnets is true about the distributions of EPS for retail and energy stocks?
Definition
The distribution of EPS for retail stocks is skewed to the left.
Term
Suppose a sample of 60 cans of soda has a mean of 12.1 ounces and a standard deviation of 0.05 ounces. If a can of soda has 12 ounces, what is its corresponding z score?
Definition
2
Term
Canned Peaches:The hypotheses to be test are Ho:mu=1000 grams Vs. Ha:mu doesnt equal 1000 gram. To exam the data, one graph was made. What assumption can be checked using this graph?
Definition
Random Sample
Term
Canned Peaches: The test is to be performed using a 5% confidence level. The observed t-test statistic is t=-2.4 and the corresponding 2 tailed p value is .022. What would have been the p-value if Ha; mu<1000 grams
Definition
.011
Term
In order to compare the man charges for the three groups, the data will be subjected to an analysis of variance. Write the null hypotheses tested by the Anova
Definition
Ho: mu C = mu E = mu I
Term
The variable measured in the experiment is called the
Definition
Response variable
Term
What is the interpretation of the standard error of sample mean?
Definition
In repeated smapling, the standard deviation of htose sample means over all possible samples (of a given size) drawn from the population.
Term
SUV Clean times: What are the factor levles for this experiment?
Definition
The time limits: 20 min, 25 min, 30 min, 35 min
Term
The variables, quantitative or qualitative, whose effect on a response variable is of interest are called
Definition
factors
Term
Which of the following is not a condition required for a valid ANOVA F-test for a completely randomized experiment?
Definition
The sample chosen from each of the populations is sufficiently large
Term
Four Leadership Styles: Interpret the results of the Anova F-test shown on the printout for a=0.05.
Definition
At a=.05, there is sufficient evidence of differnces among substandard work-scale means for the four leadersihp styles.
Term
Consider a completely randomized design with k treatments. Assume all pairwise comparison of treatment means are to be made using a multiple comparison procedure. Determine the total number of treatment means to be compared for the value k=12.
Definition
66
Term
Sample statistics are random variable, because different samples can lead to differnet value of the sample statistics
Definition
True
Term
In most situation, the true mean and standard deviation are unkown quantitites that have to be estimated.
Definition
True
Term
A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 450 seconds and a standard deviation of 50 seconds. Find the probability that a randomly selected boy in secondary school can run the mile in less than 335 seconds?
Definition
.0107
Term
We believe that 80% of the population of all business statistics I studnets consider statistics to be an exciting subject. Suppose we randomly and independently selected 36 students from the population. If the true percentage is really 80%, find the probability of observing 35 or more students who consider statistics to be an exciting subject.
Definition
.003245
Term
The Central Limit Theorem is important in statistics because
Definition
For a large, n, it says the sampling distribution of the sample mean is approximately normal, regarless of the population
Term
The daily revenue at a univerisyt sanck bar has been recorded for the past 5 years. Records indicate that the mean daily revenue is $4200 and the standard deviation is $600. The distribution is skewed to the right due to several high volume days (football game days). Suppose that 100 days are randomly selcted and hte average daily revenue computed. Which of the following describes the sampling distribution of the sample mean?
Definition
Normally distributed with a mean of $420 and a standard deviation of $60
Term
The mean of a data set is at the 50th percentile
Definition
False
Term
The coefficeint of correlation is a useful measure of hte linear relationsihp between two variables.
Definition
True
Term
A high value of the correlation coefficeint r implies that a causal relationship exists between x and y
Definition
False
Term
A low value of the correlation coefficient r implies that x and y are unrelated.
Definition
False
Term
The least Squares model provides very good estimates of y for values of x far outside the rand of x values contained in the sample.
Definition
False
Term
Best Grad and Prof. Schools:For the situation above, write the equation of the probabilistic model of interest.
Definition
Salary= B0+B1 (GMAT)+ E
Term
Best Grad and Prof. Schools: For the situation above, write the equation of the least squares line.
Definition
Salary=-92040 + 228 (GMAT)
Term
Best Grad and Prof Schools: For the situation above, give a practical interpretation of B-hat0=-92040
Definition
The value has no practical interpretation since a GMAT of 0 is nonsensical and outside the range of the sample data.
Term
Best Grad and Prof Schools: For the sitation above, Give a practical interpretation of Bhat1=228.
Definition
We estimate salary to increase $228 for every 1 point increase in GMAT
Term
Best Grad and Prof Schools: For the situation above, give a practical interpretation of r^2=.66
Definition
66% of the sample variation in SALARY can be explained by using GMAT in a straight-line method
Term
Best Grad and Prof Schools: For the situation above, give a practical interpretation of r=.81
Definition
There appeares to be a positive correlation between salary and GMAT
Term
Best Prof and Grad Schools:Set up the null and alternative hypotheses for testing wheter a positive linear relationsihp exists between salary and GMAT in the situation above.
Definition
Ho: B1=0 vs Ha: B1 does not = 0
Term
Best Prof and Grad Schools: For the situation above, give a practical interpretation of t=6.67
Definition
There is evidence (at a=.05) of at least a positive linear relationsihp between salary and GMAT
Term
Best Grad and Prof Schools: A 95% prediction interval for SALARY and GMAT =600 is ($37,915,$51,948). Interpret this interval
Definition
We are 95% confident that the salary of a top business school graduate wit ha GMAT of 600 will fall between $37,915 and $51,984
Term
Best Grad and Prof School: For the situation above, which of the following is not an assumption required for the simple linear regression analysis to be valid?
Definition
Salary is independent of GMAT
Term
In a simple linear regression model, which of the following statements is true?
Definition
none of the statements is true
Term
The process of monitoring and elimination variation in order to keep a process in a state of control or to bring a process into control is called
Definition
statistical process control
Term
The primary goal of quality imporovement activities is
Definition
to reduce variation
Term
Fastest Dying Cities:Correct Null and Alternative
Definition
Ho: P=.28 Ha: P does not equal .28
Term
Fastest Dying Cities: The correct value of the test statistic is
Definition
2.67
Term
Fastest Dying Cities: The p-value associated with the test statistic is
Definition
.0038
Term
Fastest Dying cities: At a=.05
Definition
We can conclude that the percentage of americans in these cities experiencing difficulty making mortgage payments is signifcantly higher than 28%
Term
Personal Time: Null and Alternative
Definition
Ho: mu1-mu2-0 and Ha: mu 1-mu2>0
Term
Personal Time: The t-test for two means is apprpriate in this siuation because
Definition
women and men are independent samples
Term
Personal Time: The correct value of the statistic is
Definition
2.14
Term
Personal Time: at a=.05
Definition
reject the null, conclude that women take a higher average number of hours of personal time per year, compared to men.
Term
Personal Time: Based on the data, the correct 90% confidence interval for the difference between women and men in the average number of hours of personal time taken per year is
Definition
(.57,5.21)
Term
CEO of Electric Utility: Null and Alternative
Definition
Ho: p=.8 Ha: p does not equal .8
Term
CEO of Electric Utility: What is the appropriate test statistic for testing the CEO's claim?
Definition
-1.25
Term
CEO of Electric utility:What is the rejection region for this test? Use a=0.05
Definition
x>1.96 -x<-1.96
Term
CEO of Electric utility: what would be the conclusoin, based on this test?
Definition
Do not reject Ho
Term
A p-value indicates
Definition
The probability of getting an observed statistic that is as extreme or more extreme then the current observed statistic given that the null hypothesis is true.
Term
Explain what the phrase 95% confident means when we interepret a 95% confidence interval for mu.
Definition
In repeated sampling, 95% of similarly constructed intervals contain the value of the population mean.
Term
The owner of a convenience store ahs newspapers delivered early each morning. The demand for the newspaper is normally distributed, with a mean of 50 and std deviation of 5. What is the minimum number of copies that should be ordered so that the probability of selling out is at most 15%?
Definition
56 books
Term
The random variable x represents the number of boys i na family with three children. Assuming that births of boys and girls are equally likely, find the mean and std deviation for the random variable x.
Definition
Mean 1.5, Std Deviation=8.66
Term
Intramural Football: What is the probability that the team will win 8 games
Definition
.009
Term
If the team has already won 5 games this season, what is the probability that the team will win less than 7 games?
Definition
.932
Term
Intramural Football: What is the expected number of games the team will win in any season?
Definition
4.242
Term
Normal probability plots for 4 data sets are shown below. Which plot indicates that the dta are approximately normally distributed?
Definition
II only
Term
Membership of Small College: What is the probability that the write of this letter favors the new proposal?
Definition
44%
Term
Membership for small College: Given that the writer of the letter states he/she is in favor of the new proposal, what is the probability that the letter was sent by a faculty member?
Definition
27.27%
Term
Mid Sized Company (ERP): Which of the following statements is true
Definition
This is a one tailed paired t test
Term
Mid Sized Company (ERP): Assuming that we define our differences as Post-workshop anxiety level-pre-workshop anziety level, the correct alternative hypothesis is
Definition
mu (d) <0
Term
Mid Sized company (ERP): The correct value of the test statistic is
Definition
4.054
Term
Mid Sized Company (ERP): At a=.05
Definition
We reject the null hypothesis and we can condlude that participating in this workshop reduces employee anxiety levels about ERP.
Term
Random Walk Theory of Prices: If you know that a portfolio has risen in price two years in a row, what probability do yo uassign to the event that it will go down in the 3rd year?
Definition
.35
Term
Random Walk Theory of Prices: What is the probability that the portfolio's value moves in the same direction in both of the next 2 years?
Definition
.545
Term
What notation is used to denote population mean?
Definition
mu
Term
What Notation is used to denote sample proportion?
Definition
P-hat