4) A car salesroom wanted to find out how well two new sales people were doing. The revenue for car sales for each employee was
recorded over a period of
several months, and the results were as follows:
Results for Mr Chan
Revenue (£)
fx
Midpoint
(x)
0-
50 000 -
75 000
100 000
125 000 -
150 000
Number of months
(f)
5
11
4
2
2
0
Midpoint
fx
Results for Mr Hazim
Revenue (£) Number of months
(f)
0-
6
50 000
8
75 000 -
0
U
100 000
3
125 000 -
3
150 000
0
a) Using linear interpolation find an estimate for the median monthly for each
salesman
b) Find an estimate for the mean monthly revenue for each salesman.

According to a research study, parents with young children slept 6.4 hours each night last year, on average. a random sample of 18 parents with young children was surveyed and the mean amount of time per night each parent slept was 6.8. this data has a sample standard deviation of 0.9. (assume that the scores are normally distributed.) researchers conduct a one-mean hypothesis at the 5% significance level, to test if the mean amount of time parents with young children sleep per night is greater than the mean amount of time last year. the null and alternative hypotheses are h0: μ=6.4 and ha: μ> 6.4, which is a right-tailed test. the test statistic is determined to be t0=1.89 using the partial t-table below, determine the critical value(s). if there is only one critical value, leave the second answer box blank.