1.

Facing a budget shortage, the student activity council decides to reduce funding for each of its student clubs by $85. Prior to the cut, the average funding that each student club received was $520, although some received more while others received less than $520. On average, the funding received differed from the mean by $55. What effect will the budget cut have on the amount of variability? What will be the new standard deviation of the distribution?

2.

On average, a used two-year-old Honda Civic sells for $11,835. Suppose you bought one for just $10,500. Which scenario would suggest that you got a better deal, one in which the standard deviation of the purchase price is $900, or when the standard deviation is $1,500?

3. Roskos-Ewoldsen, Black, and McCown (2008) compared the performance on a visual working memory task between younger adults and older adults. They found that the younger adults scored an average of 10.98 on this test with a standard deviation of 3.38, while older adults scored, on average, 3.86, with a standard deviation of 3.90.

a. Which group performed better on the test, the younger adults or the older adults? Which measure of descriptive statistic did you use to arrive at your answer?

b. Which group had scores that were more variable, the younger adults or the older adults? Which measure of descriptive statistic did you use to arrive at your answer?

4. A sample of scores has a standard deviation of zero. What does this mean about the scores in the sample?

5. Your friend Lora would like to describe the scores in a dataset that she obtained. She found that theSSof the scores in the data is -4700 and the variance is -470. When she tried to calculate the standard deviation, however, the calculator displayed an error message. Explain why this might be the case.

6. A school administrator is reviewing the performance on the science test among a few of the eighth-grade students who took the Pennsylvania System of School Assessment (PSSA). The students' scores were 1320, 1498, 1810, 1289, 1237, and 1432. Calculate (a) the sum of squares, (b) variance, and (c) standard deviation, and (d) interpret the standard deviation. Be sure to clearly label your answers.

7. CHALLENGE QUESTION (OPTIONAL): Suppose you conducted two studies, each with two groups. The following are the data you obtained for the two studies:

Study 1: Group 1:M= 75,s= 3 Group 2:M= 70,s= 3

Study 2: Group 1:M= 75,s= 50 Group 2:M= 70,s= 50

In each study, there appears to be a difference between the two sample means (75 vs. 70). In which study would you need a larger sample size in order to detect this difference? Why?