Which of the following are measures of central tendency? Select all that apply

mean

median

mode

Variance

standard deviation

linear transformation

Which of the following are measures of variability? Select all that apply

mean

median

mode

variance

standard deviation

linear transformation

Rachael and Peter are discussing how the mean value and variance affect the distribution graph. As the following graph shows, there are two distributions: A and B

Peter said that the distribution A has fatter tail because its has bigger standard deviation than the distribution B. Rachael’s answer is different:she thinks the distribution A has a smaller standard deviation than the distribution B.

Who do you think is right?

Peter

Rachael

None of them are right. Distribution A and Distribution B have the same standard deviation

In a bell-shaped distribution, changing ___can make the distribution flatter (i.e. more compressed); and changing ___ can shift the distribution to the left or to the right.

Variance, mean

Mean, variance

Range, standard deviation

Mode, range

Mean, range

Mode, variance

A research study found that in one physics class, the correlation between pre-exam and post-exam grades was 0.90. The variance of pre-exam grades was 9 and the variance of post-exam grades was 16. Thus, the variance of the difference between pre-exam and post-exam grades is: (show work)

Image that a researcher examined how the people’s heights are associated with their salaries. She found that the correlation between heights (measured in inches) and salary range (measured in dollars) was .36. Had she measured the height in cm instead, what would the correlation have been?

0.36

0.036

3.6

0.72

0.18

The variance of X is 64 and the variance of y is 36. X and Y are independent. Thus, the sum of the variances between X and Y is: (show work)

A research study found that for the new-coming medical students, the correlation between the trail Medical College Admission Test (MCAT) grades and real MCAT grades was 0.60. The variance of pre-exam grades was 81 and the variance of post-exam grades was 100. Thus, the variance of the difference between pre-exam and post-exam grades is: (show work)

One of the hallmarks of the scientific method is that it depends on empirical data.

True

False

The best way to code a height measure of 1.8 meters would be to____

Have the subject write their height in inches

Have the subject record the information how they are comfortable, and then have the researchers convert it over to inches if necessary

Leave it as is; the computer understands this notation

If you wished to know how long since your subjects had eaten breakfast, it would be better to ask them_____

What time they ate their breakfast and what time it is now

How many minutes since they ate breakfast

The flaw in which a study samples too few observations from a segment of the population is called___

Undercoverage bias

Survivorship bias

Self-selection bias

In a normal distribution, __ percentage of the area under the curve is within three standard deviations of the mean?

68%

50%

95%

99%

A normal distribution with a mean of 10 and standard deviation of 5. What is the corresponding Z score for a case having a value of 7? (show work)

For a normal distribution with a mean of 20 and standard deviation of 2, what is the probability of getting a number greater than 26?

5%

2.5%

1%

0.5%

A binomial distribution is a probability distribution for ____ events for which there are ___ possible outcomes

Independent; two

Dependent; two

Independent; multiple

Dependent; Multiple

In the figure above, what is an estimate the calories for a cereal with carbohydrate of 35 and fat of 5?

between 75-100

between 100-125

between 125-150

between 150-175

between 175-200

greater than 200

The contour map shown above indicates that as fat and carbohydrates increase, calories increase but not at a constant rate.

True

False

The figure above shows…

data that follows the assumed distribution.

data that does not follow the assumed distribution.

The q-q plot can be used to formally test the _________ hypothesis that the data are normally distributed. This is done by computing the correlation coefficient of the n points in the q-q plot.

null

alternative