Posted: April 12th, 2016

how large would the sample have to be?

Before conducting a maze learning experiment you weigh two groups of rats. The experimental group, which contains 20 rats, has an average weight of 18 ounces, while the control group, which contains 10 rats, has an average weight of 15 ounces. What would be the average weight of the two groups?
1. 16
2. 16.5
3. 17
4. 18
The sum of all of the deviations from the mean:
1. is always positive
2. is always negative
3. is always zero
4. depends on the number of scores
If all of the scores in a distribution are multiplied by the same constant:
1. the standard deviation will be multiplied by that constant
2. the standard deviation will be divided by that constant
3. the standard deviation will be equal to that constant
4. the standard deviation will be unchanged
What is the median of the following set of numbers: 19, 7, 6, 0, +2, +4?
1. 3
2. 6
3.
4. +3
Given the following set of numbers: 1, 3, 3, 5, 28, what is the value for the sum of squares (SS) ?
1. 320
2. 508
3. 828
4. 1600
If the unbiased standard deviation has been calculated for a sample of 12 subjects, and s is 3, what would be the value for the sum of squares (SS) measured for the same 12 subjects?
1. 7.66
2. 36.7
3. .945
4. 9.95
The standard deviation of a set of z scores:
1. always equals 0
2. always equals 1
3. depends on the number of scores
4. depends on the shape of the distrubution
On a midterm exam, your score expressed as a z score is 1.50. The mean of the exam is 70 and the standard deviation is 8. Your raw score is:
1. 54
2. 58
3. 82
4. 86
Assume that the heights of woman in 12th grade in the Virginia is 61.5 inches and the standad deviation is 6.5 inches. If groups of size 9 are randomly chosen and the means plotted, what is the probability of selecting a group whose height is between 56 and 58 inches? Remember, area = probability. Even with rounding your answer should be very close to the correct choice.
1. .1228
2. .8970
3. .0086
4. .0471
Assume the mean number of times Americans exercise per week is equal to 2, with a standard deviation of .55. What is the standard error of the mean for a sample size of 30?
1. .02
2. .10
3. .37
4. 3.64
If the mean weight for all men is 160 pounds with a standard deviation of 20 pounds, and you want the standard deviation of the sampling distribution to be 1 pound, how large would the sample have to be? You may consult the formulas at the end of chapter 4.
1. 20
2. 40
3. 160
4. 400