PY 211 midterm exam chapter 3

sample size

# of individuals comprising a subset of a population

Population size

# of individuals comprising an entire group

median position formula

(n+1)/2

True or false: when the mean is greater than the mode, the distribution is negatively skewed.

false

How do you find the median for even number of scores?

find the median position and average around it

when do you use the median position?

finding median for odd #'s of scores

add a score above the mean and the mean will___

increase

delete a score below the mean and the mean will___

increase

mean, median and mode can be used for what scales of measurement?

interval/ration

when the mode is greater than the mean it is ____skew

left

Median

the middle score in a distribution; half the scores are above it and half are below it

A sports psychologist uses the body mass index (BMI) score to measure health in a sample of 60 athletes and determines that 20 are normal, 26 are overweight, and 14 are obese. Which measure of central tendency is most appropriate for describing these data?

the mode

Mode

the most frequently occurring score(s) in a distribution

mean

the sum of the scores divided by the total number of scores

add or delete a score equal to the mean and the mean___

will not change

Identify the mode: a study reports that women are more likely to ask for directions than men.

women

What type of distribution is used to approximate the median?

Cumulative percent distribution

A scientist records the following sample of scores (n=6): 3,2,4,1,10,12. what is the sample mean of these scores?

M=6

population notation

N

The notation used in the formulas for sample mean and population mean differs. What notation differs in these formulas?

N is for the denominator for the population mean and n is for the denominator for the sample mean

___symbolizes the size of a population, whereas ___ symbolizes the size of a sample

N;n

The calculations of a population mean and a sample mean is the same. State in words how to compute the mean.

The mean is the sum of a set of scores/ the total number of scores

add a score below the mean and the mean will___

decrease

Which of the following will decrease the value of the mean?Deleting a score below the mean Add a score below the mean Add a score exactly equal to the mean None of the above

add a score below the mean

The mean is a preferred descriptive statistic: For describing normal distributions For summarizing interval scale measures For summarizing ratio scale measures All of the above

all of the above

When the mean equals or doesn't equal the median but there ae 2 modes what is the distribution?

bimodal

delete a score above the mean and the mean will ___

decrease

All measures of central tendency have a tendency to be at or near the ___ of a distribution

center

The mean is the most commonly reported measure of:

central tendency

Median should be used when

data is skewed in one direction, median is not influenced by outliers, ordinal; direction only not distance focused

What does the median represent?

midpoint of a distribution

The ___is the preferred measure of central tendency when a data set has outliers

mode

sample notation

n

mode should be used when

nominal scale, qualitative response, unusual distribution of data, bimodal or multimodal

When the mean, median, and mode are all equal it is ____

normal distribution

Mean should be used when

normal distribution of data, uses all scores in calculations, interval or ratio

When would you need to understand the shape based on central tendency circumstances?

only mean, median or mode, educated guess at shape of distribution, interval/ ratio scale w/o table or graph

A researcher records the levels of attraction for various fashion models among college students. He finds that mean levels of attraction are much higher than the median and mode for these data. What is the shape of the distribution for the data described in this study?

positively skewed distribution

A researcher records the number of hours (per week) that adults spend on social media and finds that the data are distributed normally. Which measure of central tendency is most appropriate for describing these data?

the mean

when the mean is greater than the mode it is ___skew

right

central tendency

single score that is most representative or descriptive of all scores/ categories in a distribution