Question

In: Statistics and Probability

At a large university, freshmen students are required to take an introduction to writing class. Students...

At a large university, freshmen students are required to take an introduction to writing class. Students are given a survey on their attitudes towards writing at the beginning and end of class. Each student receives a score between 0 and 100 (the higher the score, the more favorable the attitude toward writing). The scores of nine different students from the beginning and end of class are shown below. Use the Wilcoxon signed-rank test to check at a 5% significance level whether the attitudes toward writing appear to increase by the end of the class?

Beginning 77.6 83.2 60.2 93.1 74.6 43.1 86.9 79.3 80.2
End 85.4 79.6 64.2 96.6 79.3 40.5 90.1 89.2 85.6

Solutions

Expert Solution

Beginning End difference=sample1-sample 2 absolue difference rank rank if positive rank if negative
77.6 85.4 -7.8 7.8 8 8
83.2 79.6 3.6 3.6 4 4
60.2 64.2 -4 4 5 5
93.1 96.6 -3.5 3.5 3 3
74.6 79.3 -4.7 4.7 6 6
43.1 40.5 2.6 2.6 1 1
86.9 90.1 -3.2 3.2 2 2
79.3 89.2 -9.9 9.9 9 9
80.2 85.6 -5.4 5.4 7 7

Ho :median difference=   0
Ha: median difference >   0
  
Level of Significance , α =    0.05
  
number of non zero difference , n =    9
  
sum of positive ranks, W+ =    5
sum of negative ranks , W- =   40
  
T = W+ = 5

The critical value for the signficance level α=0.05 provided, and the type of tail specified is T∗ =8, and the null hypothesis is rejected if T≤8.

(3) Decision about the null hypothesis

Since in this case, T=5≤8, there is enough evidence to claim that the attitudes toward writing appear to increase by the end of the class, at the α=0.05 significance level.


Related Solutions

In a large midwestern university (the class of entering freshmen is 6000 or more students), an...
In a large midwestern university (the class of entering freshmen is 6000 or more students), an SRS of 100 entering freshmen in 1999 found that 20 finished in the bottom third of their high school class.  Admission standards at the university were tightened in 2000.  In 2001, an SRS of 100 entering freshmen found that 10 finished in the bottom third of their high school class.  Let p1 and p2 be the proportion of all entering freshmen in 1999 and 2001, respectively, who...
In a large midwestern university (the class of entering freshmen is 6000 or more students), an...
In a large midwestern university (the class of entering freshmen is 6000 or more students), an SRS of 100 entering freshmen in 1999 found that 20 finished in the bottom third of their high school class. Admission standards at the university were tightened in 2000. In 2001, an SRS of 100 entering freshmen found that 10 finished in the bottom third of their high school class. Let p1 and p2 be the proportion of all entering freshmen in 1999 and...
QUESTION 5 In a large midwestern university (the class of entering freshmen is 6000 or more...
QUESTION 5 In a large midwestern university (the class of entering freshmen is 6000 or more students), an SRS of 100 entering freshmen in 1999 found that 25 finished in the bottom third of their high school class. Admission standards at the university were tightened in 2000. In 2001, an SRS of 100 entering freshmen found that 15 finished in the bottom third of their high school class. Let p1 and p2 be the proportion of all entering freshmen in...
A statistics professor at a large university hypothesizes that students who take statistics in the morning...
A statistics professor at a large university hypothesizes that students who take statistics in the morning typically do better than those who take it in the afternoon. He takes a random sample of 36 students who took a morning class and, independently, another random sample of 36 students who took an afternoon class. He finds that the morning group scored an average of 72 with a standard deviation of 8, while the evening group scored an average of 68 with...
The introductory biology class at a large university is taught to hundreds of students each semester....
The introductory biology class at a large university is taught to hundreds of students each semester. For planning purposes, the instructor wants to find out the average amount of time that students would use to take the first quiz if they could have as long as necessary to take it. She takes a random sample of 100 students from this population and finds that their average time for taking the quiz is 20 minutes, and the standard deviation is 10...
Students at Upscale University are required to take at least 4 humanities and 4 science courses....
Students at Upscale University are required to take at least 4 humanities and 4 science courses. The maximum allowable number of science courses is 12. Each humanities course carries 4 credits and each science course 3 credits. The total number of credits in science and humanities cannot exceed 60. Quality points for each course are assigned in the usual​ way: the number of credit hours times 4 for an A​ grade, times 3 for a B​ grade, and times 2...
3. A sample of 25 freshmen and senior students at a major university completed a survey...
3. A sample of 25 freshmen and senior students at a major university completed a survey that extent of satisfaction with the parking situation on the campus (the higher the score, the greater the satisfaction).                                   Freshmen 11              43                30                30                   45 41              12                40                42                   35       45              25                10                33                   50 42              32                38                11                   47     22              26                37                38                   10                                  Seniors 10             45               35                  28                  52 35             12               50                  40                  30 40             10               10                  38                  12 40            ...
Each year about 1500 students take the introductory statistics course at a large university. This year...
Each year about 1500 students take the introductory statistics course at a large university. This year scores on the final exam are distributed with a median of 74 points, a mean of 70 points, and a standard deviation of 10 points. There are no students who scored above 100 (the maximum score attainable on the final) but a few students scored below 20 points. a.Is the distribution of scores on this final exam symmetric, right skewed, or left skewed? b.Would...
a consultant for a large university studied the number of hours per week freshmen watch tv...
a consultant for a large university studied the number of hours per week freshmen watch tv versus the number of hours seniors do. the results of this study follow. is there enough evidence to show the mean number of hours per week freshmen watch tv is different from the mean number of hours seniors do at alpha=.1. freshmen n=10, xbar=18.6, s=7.8740 seniors n=4, xbar=11.4, s=3.9749
a consultant for a large university studied the number of hours per week freshmen watch tv...
a consultant for a large university studied the number of hours per week freshmen watch tv versus the number of hours seniors do. the results of this study follow. is there enough evidence to show the mean number of hours per week freshmen watch tv is different from the mean number of hours seniors do at alpha=.1. freshmen n=10, xbar=18.6, s=7.8740 seniors n=4, xbar=11.4, s=3.9749
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT