Exam 12: Data Bank

An instructor divided her class into four groups and asked them to keep track of the number of soft drinks they consume per week. In preparation for using the Kruskal-Wallis test to test if there is a significant difference in mean weekly consumption among the 4 groups, combine and rank the following

If a researcher were interested in determining whether or not two groups ( $n = 50 )$ of students received significantly different grades in statistics, the Wilcoxon rank sum test would be the best method to use.

Given the following data, what is the ranking of data point 24? 27, 24, 17, 30, 34, 29, 12, 24

A researcher collects data on the distance between college students' high schools and their colleges. He believes that the median distance is 200 miles. A random sample of 15 students yields the following data: $2525303045455575851101351751958102170$ At $= .05$ , should the researcher's hypothesis be accepted or rejected? You may use the following abbreviated table of critical values (two tailed, $= .05$ ) taken from Table J: 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 critical valuc 1 2 2 3 3 3 4 4 4 5 5 5 6 6 6

Two independent samples of tall and short students are selected, and their scores on a 25-point statistics quiz are recorded as shown in the table below. What is the rank of the score for Wilt? Tall Short 22 17 24 20 19 24 21 22 17 19 20 (Wilt) 24 15 19 24 20 23 22 19 21

For a random sample of 60, if 45 values are below the median and the rest are above. Find the value of the test statistic.

A statistics teacher wanted to see whether students exit the classroom at random. He observes students leaving in the order given below. How many runs are present? Test for randomness at $\alpha = 005$ .

A landscaping company hypothesizes that they can mow a median number of 20 lawns in one weekend. A random sample of 14 weekends yields the following data: 22 18 19 20 25 20 18 22 23 20 21 26 24 22 -Is the landscaping company's hypothesis of a median of 20 lawns per weekend valid?

A run is a succession of identical letters preceded or followed by a different letter or no letter at all, such as the beginning or end of the succession.

If a researcher wanted to prove that there is a relationship between two variables and had collected 30 data points for each group, the Spearman rank correlation coefficient could be used, but Pearson's correlation coefficient would be a better choice for a test method.

What is the term for a nonparametric test that is used to determine the randomness of a sample?

The data collected for studying whether or not there is a difference between the number of hours men and women watch television is summarized below. To compute the test value, the data from both samples should be combined, arranged in order, and ranked according to each group. What is the sum of the ranks for each group? Ment Hous Watchiny T.V. Women: Hous Watching T.V. 2.0 20 1.5 2.5 3.0 1.0 2.5 1.0 2.0 1.5 1.0 2.5 0.0 20 2.0 1.0 1.5 2.0 25 1.5 2.0 1.0 20 0.0

A researcher believes that the median amount of rain per year is 36 inches. A random sample of 20 years yields the following data: 1921222527273137373941424549505153556166 At $= .05$ , should the researcher's hypothesis be accepted or rejected? You may use the following abbreviated table of critical values (two tailed, =.05) taken from Table J : 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 critical value 1 2 2 3 3 3 4 4 4 5 5 5 6 6 6

Six second grade students tried tossing a ball into a basket ten times each. Their teacher then suggested a different way of tossing the ball, and the six students tried again. The number of successful tosses, before and after the teacher's added instruction, are shown below. Student Successful Tosses Before (out of 10) Successful Tosses After (out of 10) A 3 5 B 5 5 C 5 2 D 3 5 E 5 2 F 5 5 What are the absolute values of the differences?

A landscaping company hypothesizes that they can mow a median number of 20 lawns in one weekend. A random sample of 14 weekends yields the following data: 22 18 19 20 25 20 18 22 23 20 21 26 24 22 -What is the test value?

We want to see if the median is greater than 25. In a random sample of 55, 15 values are below the median and the rest are above. Find the test statistic.

Two independent sets of data are collected, one with 15 subjects and one with 22 subjects. Ms. X is in the first set of data and has a value of 41. In the first set, 11 values are higher than 41 and 3 values are lower (with Ms. X being the other data value). In the second set, 16 values are higher than data and 6 values are Lower. What is the rank of Ms. X?

The computations for the rank correlation coefficient for nonparametric data are simpler than those for the ___________ coefficient and involve ranking each set of data. ________________________________________

A study of the effects of a chemical additive on soil acidity recorded the soil acidity of eight plots of land before and after the application of the additive. The results were: Plot 1 2 3 4 5 6 7 8 Before 10 8 9 7 8 6 9 11 After 8 7 7 8 6 6 8 8 The test value for the sign test is:

A researcher believes that response time for rats is effected by a certain drug. He looks at 36 rats and compares their response times before and after taking the drug. The sum of positive ranks (before - after) is 266 and negative ranks 400. Find the value of the test statistic.