Question

Generally, the average typing speed is 54 words per minute (wp). A professor wanted to see where his students stand compared to the population. He tested 28 of his students and obtained the following estimates: an average typing speed of 46 with a standard deviation of 18. What can the professor conclude with α = 0.01?

a) What is the appropriate test statistic?
---Select--- na z-test One-Sample t-test Independent-Samples t-test Related-Samples t-test

b)
Population:
---Select--- the professor typing speed average typing speed the students student typing speed
Sample:
---Select--- the professor typing speed average typing speed the students student typing speed

c) Compute the appropriate test statistic(s) to make a decision about H₀.
(Hint: Make sure to write down the null and alternative hypotheses to help solve the problem.)
critical value =  ; test statistic =  
Decision:  ---Select--- Reject H0 Fail to reject H0

Answer 1

(A) this is an example of one sample t test because population standard deviation is unknown and sample size is less than 30

(B) Population is the set of all data items and sample is the set of seleted data items from the population

So, population is average typing speed

and

sample is the  the students student typing speed

(C)

Using TI 84 calculator

press stat then tests then TTest

enter the data

mu(not) = 54

xbar = 46

s = 18

n = 28

press calculate

we get

test statistic = -2.35

t critical = T.INV.2T(alpha,n-1)

= T.INV.2T(0.01,27)

= -2.77 to 2.77

At 0.01 significance level, we failed to reject Ho because test statistic is between t critical values