Question

Generally, the average typing speed is 56 words per minute (wp). A professor wanted to see where his students stand compared to the population. He tested 30 of his students and obtained the following estimates: an average typing speed of 49 with a standard deviation of 16. What can the professor conclude with α = 0.01?

If appropriate, compute the CI. If not appropriate, input "na" for both spaces below.
[  ,  ]

e) Compute the corresponding effect size(s) and indicate magnitude(s).
If not appropriate, input and/or select "na" below.
d =  ;   ---Select--- na trivial effect small effect medium effect large effect
r² =  ;   ---Select--- na trivial effect small effect medium effect large effect

f) Make an interpretation based on the results.

Student typing speed is significantly higher than average.The average typing speed is significantly higher than student typing speed.    Student typing speed did not significantly differ from the average.

Answer 1

e)

In this problem we should do t-test for single mean. Values for 'd' or 'r² ' are taken to be considered when we test significance of difference of two sample means.

For the independent samples T-test, Cohen's d is determined by calculating the mean difference between your two groups, and then dividing the result by the pooled standard deviation. Cohen's d is the appropriate effect size measure if two groups have similar standard deviations and are of the same size.

Hence, for this problem d = NA and r² = NA.

f)