A. $6,984
B. $10,356
C. $10,476
D. $13,968
E. $20,709
Which of these explains why t should be used instead of z for inference procedures for means.
A. The Central Limit Theorem applies to proportions but not means.
B. We use z for proportions because proportions are approximately normal. Means are not.
C. We use z for proportions because the sampling distribution of sample proportions is
approximately normal, but that is not the case for the sampling distribution of sample means.
D. The sampling distribution of sample means is a t -distribution, not a z -distribution.
E. When using the sample standard deviation to estimate the population standard deviation, more
variability is introduced into the sampling distribution of the statistic.
Which of the following is least likely to reduce bias in a sample survey?
A. Following up with those who did not respond to the survey the first time
B. Asking questions in a neutral manner to avoid influencing the responses
C. Using stratified random sampling rather than simple random sampling
D. Selecting samples randomly
E. Allowing responses to be anonymous
In a study to determine whether there is a difference in color preferences for young children based
on their gender, researchers had a random sample of children choose from a selection of toys that
were identical except for their color. The table below shows the number of each color that was
chosen by boys and by girls.
How many degrees of freedom should be used in a test of independence of gender and color
preference?
A. 2
B. 4
C. 9
D. 10
E. 137
A local library has a scanner to detect library materials that have not been checked out. Each item
has a chip somewhere inside. Upon checkout, the chip is deactivated so the scanner will not set off