Question

Medical research has shown that repeated wrist extension beyond 20 degrees increases the risk of wrist and hand injuries. Each of 24 students at a university used a proposed new computer mouse design. While using the mouse, each student's wrist extension was recorded. Data consistent with summary values given in a paper are given. Use these data to test the hypothesis that the mean wrist extension for people using this new mouse design is greater than 20 degrees. (Use

α = 0.05.

Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)

28	26	27	25	28	24	24	27	27	27	24	26
22	24	27	26	28	25	31	24	26	28	28	24

t	=
P-value	=

State your conclusion.

a. Reject H₀. We have convincing evidence that the mean wrist extension for all people using the new mouse design is greater than 20 degrees.

b. Do not reject H₀. We do not have convincing evidence that the mean wrist extension for all people using the new mouse design is greater than 20 degrees.   

c. Reject H₀. We do not have convincing evidence that the mean wrist extension for all people using the new mouse design is greater than 20 degrees.

d. Do not reject H₀. We have convincing evidence that the mean wrist extension for all people using the new mouse design is greater than 20 degrees.

Are any assumptions required in order for it to be appropriate to generalize the results of your test to the population of students from this university?

a. We need to assume that the 24 students used in the study are representative of all students who own PCs.

b. We need to assume that the 24 students used in the study are representative of all students at the university.    

c. We need to assume that the 24 students used in the study are representative of all students with a history of wrist or hand injuries.

d. We need to assume that the 24 students used in the study are representative of all students who use a wireless mouse.

e. We need to assume that the 24 students used in the study are representative of all students in computer science classes.

Are any assumptions required in order for it to be appropriate to generalize the results of your test to the population of all university students?

a. We need to assume that the 24 students used in the study are representative of all university students.

b. We need to assume that the 24 students used in the study are representative of all students in computer science classes.    

c. We need to assume that the 24 students used in the study are representative of all students who own PCs.

d. We need to assume that the 24 students used in the study are representative of all students who use a wireless mouse.

e. We need to assume that the 24 students used in the study are representative of all students at the university.

Answer 1

One-Sample T: Wrist Extension

Descriptive Statistics

N	Mean	StDev	SE Mean	95% Lower Bound for μ
24	26.083	1.998	0.408	25.384

μ: mean of Wrist Extension

Test

Null hypothesis	H₀: μ = 20
Alternative hypothesis	H₁: μ > 20

T-Value	P-Value
14.91	0.000

So, t = 14.91 & P-value = 0.000

(a) Reject H₀. We have convincing evidence that the mean wrist extension for all people using the new mouse design is greater than 20 degrees.

(b) We need to assume that the 24 students used in the study are representative of all students at the university.    

(e) We need to assume that the 24 students used in the study are representative of all students at the university.