# Shared Flashcard Set

## Details

Biostats
MIDTERM 2021
65
Other
10/15/2021

Term
 What are those two groups that Biostats is divided in?
Definition
 1. Descriptive2. Inferential
Term
 What are the measures of central tendency?
Definition
 The Mean, The Median and The Mode
Term
 It is the most frequently value occurring in a dataset:A. MedianB. MeanC. Mode
Definition
 C. The Mode
Term
 What is called the middle value in a ordered list of values from the smallest to the largest?A. MeanB. Modec. Median
Definition
 C. Median
Term
 Inferential statistics allows to make general assumptions about a population. TRUE or FALSE?
Definition
 True: with Inferential Biostatistics you take data from samples of objects from a population and make generalizations about a larger population of subjects.
Term
 Inferential Biostatistics are NOT good for comparing treatment drugs. TRUE or FALSE?
Definition
 FALSE: Inferential Biostatistics are used to compare differences between treatment groups.
Term
 Significancy of a sample are composed by the characteristics of a sample that best describe a population. TRUE or FALSE?
Definition
 TRUE: it is essential that the sample is significative to accurately predict the population.
Term
 What does the Gaussian Curve show?
Definition
 A normal distribution
Term
 When we say that a probability distribution is symmetric about the mean we are referring to:
Definition
 NORMAL DISTRIBUTION or GAUSSIAN CURVE (Bell curve)
Term
 The Central Limit Theorem states that if you have a population with a MEAN and a STANDARD DEVIATION and take suffiCIently large samples from the population WITH REPLACEMENT, then the distribution of the SAMPLE MEAN will be approximately normally distributed. TRUE or FALSE?
Definition
 TRUE
Term
 What is the proportion of a population/sample between the MEAN and a +1SD?
Definition
 34.13%
Term
 In a normal distribution, a percentile 50 matches with:A. MEANB. MEDIANC. BOTHD. NONE
Definition
 "C: BOTH" In a normal distribution, the mean, median, and mode all have a corresponding z-score of 0 and are the 50th percentile.
Term
 in an asymmetrical distribution, where is the tail located when is positive skewed?
Definition
 THE TAIL IS IN THE RIGHT
Term
 Starting from left to right, what is the other of the central tendency measurements when it is a negative skewed distribution?
Definition
 From left to right: MEAN , MEDIAN and MODE
Term
 What the order (from left to right) of the Median, Mode and Mean when the values al positive skewed?
Definition
 MODE, then MEDIAN and finally the MEAN
Term
 What's the lowest value in a positive skewed distribution?
Definition
 THE MODE
Term
 What's the lowest value in a negative skewed distribution?
Definition
 THE MEAN
Term
 What is the hightest value in a positive skewed distribution?
Definition
 THE MEAN
Term
 What's best definition for the following:μ > M > Modea. Symetrical distributionb. Positive skewedc. Negative skewed
Definition
 B. POSITIVE SKEWED
Term
 What is another name for Leptokurtosis?
Definition
 POSITIVE KURTOSIS
Term
 In a distribution with positive Kurtosis: A) Heavier tails than normal distributionB) Weaker tails than normal distributionC) Same tails as normal distributionD) There are more values in the tails than in normal distributionE) A + DF) B + DG) NONE OF ABOVE
Definition
 "E" Positive Kurtosis has heavier tails and so more values in the tails than in a Normal Distribution
Term
 Leptokurstosis has more data in the tails than in the normal distribution: true or false
Definition
 TRUE: It has a heavier tail:more datas in the tails. This causes HIGH PEAKS.
Term
 Positive Kurtosis tend to have heavy outliers. When can you say it is a positive kurtosis?A. Kurtosis is =1B. Kurtosis is < 3c. Kurtosis is > 1d. Kurtosis is > 3e. Kurtosis is > 0
Definition
 D: Image result for pOSITIVE KURTOSIS HIGH PEAKSIf the kurtosis is greater than 3, then the dataset has heavier tails than a normal distribution (more in the tails).
Term
 How do you interpretate when a Kurtosis value is less than 3?
Definition
 That the dataset has lighter tails thus the it is normally distributed.
Term
 What is Platykurtosis?
Definition
 NEGATIVE CURTOSIS
Term
 How do you call when you have a dataseet with an excess of extreme values and so your distribution is flatter than the normal distribution?
Definition
 NEGATIVE KURTOSIS
Term
 What type of variable is the Blood Type?A. NOMINALB. ORDINALC. CONTINIOUS
Definition
 A. NOMINAL
Term
 ORAL HYGIENE INDEX is a a variable type:1. Discrete2. NOMINAL3. ORDINAL
Definition
 3. ORDINAL
Term
 AGE is a variable type:A. OrdinalB. NominalC. ContinuosD. Discrete
Definition
 A/B : age could be both nominal or ordinal
Term
 Satisfaction Level is a variable type:A. OrdinalB. NominalC. Continuos
Definition
 A. Ordinal
Term
 Years of Education is a variable type: A. Ordinal B. Nominal c. continuos
Definition
 A. Ordinal/ Continuos
Term
 In count or discrete variable: there is no decimal numbers (1.15, 2.50, etc)¿TRUE OR FALSE?
Definition
 TRUE: only whole numbers are included, starting from 0 to INFINITE.
Term
 Number of cavities in an oral cavity:A) NOMINALB) CONTINUOSC) ORDINALD) NONE OF ABOVE
Definition
 D) NONE OF ABOVE: The answer is DISCRETE because you count cavities from 0
Term
 LEVELS of CHOLESTEROL in BLOOD:A) NominalB) DiscreteC) ContinuosD) Ordinal
Definition
 C) CONTINUOS (if it has numbers) or D) (if you clasify them as high - medium - low)
Term
 A Parameter is associated with:A) SAMPLEB) POPULATION
Definition
 B: POPULATION
Term
 A Statistic is associated with:A) SAMPLEB) POPULATION
Definition
 A) SAMPLE
Term
 Write the Normal Distribution equation
Definition
 x - µ / σ
Term
 Write the STANDARD NORMAL DISTRIBUTION equation
Definition
 x - µ / σ
Term
 Write the formula of how to find µ
Definition
 µ = n x p
Term
 Write the formula of σ (Population Standard Deviation)
Definition
 σ = √ n x p x q
Term
 Write the formula to find "Z"
Definition
 Z = (x - 0.5) - µ / σ
Term
 What is the formula to find the Median?
Definition
 Median = N + 1 / 2 . The result is the order of the value arranged in increasing order.
Term
 Write the formula to find the variance in POPULATION and in SAMPLE.
Definition
 [image]
Term
 Write three symbols of population parameters and tell if they all are measured in the same units.
Definition
Term
 A numerical measure computed from a sample, such as sample mean, is known as aa.population parameterb.sample parameterc.sample statisticd.population mean
Definition
 C: Sample statistic
Term
 A numerical measure, such as a mean, computed from a population is known as aa.population parameterb.sample parameterc.sample statisticd.sample mean
Definition
 A: Population parameter
Term
 Which of the following descriptive statistics is not measured in the same units as the data?a.35th percentileb.standard deviationc.varianced.interquartile range
Definition
 A) The 35th percentile
Term
 How do you obtain the sample to obtain external validity?
Definition
 By randomizing
Term
 What are the two properties that sample size influences on?
Definition
 1. The power of the study to draw conclusions2. The precisions of the estimates
Term
 What does random sampling ensure?
Definition
 Random sampling ensures external validity . Less bias.
Term
 The sample mean is an unbiased estimator of the population mean. TRUE or FALSE
Definition
 TRUE
Term
 The sample range is an unbiased estimator of the population range. TRUE OR FALSE?
Definition
 FALSE: Range is ALWAYS BIASED
Term
 If I have a dataset of 7 values, how do I find the median?
Definition
 7+1 / 2 = THE FOURTH VALUE of the data set is the median.
Term
 The estimated precision of the sample mean increases with ___________
Definition
 THE SAMPLE SIZE
Term
 CAN YOU CALCULATE THE GEOMETRIC MEAN WHEN AN OBSERVATION INCLUDES 0 (ZERO)?
Definition
 NO: You can only calculate geometric mean when the values of the observations are greater than zero.
Term
 When are the geometric and arithmetic mean the same?
Definition
 They will only be equal when the variance is ZERO.
Term
 What do you use to remove positive skew?
Definition
 LOG TRANSFORMED DATA
Term
 What happens to the geometric mean when you use LOG TRANSFORMATION DATA to remove positive skewness?
Definition
 The gemoetric mean INCREASES.
Term
 Is random sampling sufficient to ensure external validity?
Definition
 NO: Because some subjects may decline to participate
Term
 Name 4 SAMPLE MEASURES of spread (dispersion)
Definition
 1. Standard Deviation2. Variance3. Ranges4. Interquartile ranges
Term
 When do you use the geometric mean?
Definition
 When the data values are expressed in RATIOS or in PERCENTAGES
Term
 The sample variance is unbiased: TRUE or FALSE?
Definition
 TRUE. It's not biased
Term
 How do you calculate a QUARTILE when n is ODD?
Definition
 If N is odd: n + 3 / 4
Term
 How to calculate q quartile range when n is even?
Definition
 If N is even: n+2/4
Term
 What's the equation to find a MEDIA?
Definition
 N+1/2
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