I'm having a bit of trouble with these two questions. Am I on the right track for the first q and am i using the right formula? and any ideas on how to work out the second question. thanks

In an attempt to examine the historical difference between two investments, the return from each investment was recorded over the last 10 reporting periods. The results were:

PERIOD 1 2 3 4 5 6 7 8 9 10
INVESTMENT 1 9.2 6.0 12.5 7.0 6.7 9.4 9.4 7.1 5.7 6.6
INVESTMENT 2 6.8 7.3 11.2 8.6 10.5 9.1 6.4 7.5 0.7 2.8

Assuming the investment returns are normally distributed, can we conclude that the average rate of return for Investment 1 is greater than the average return for Investment 2 at the 5% level of significance?

For this question do I just

Calculate the differences
enter the differences
Calculate the mean difference (d)
And the standard deviation of the differences (SD)
Using the formula (t- test), find the value of t.


A weight-loss company claims that its weight-loss program is superior to its competitor. To test this claim, a group of 16 overweight male volunteers were randomly allocated to one program or the other and the weight losses over a 3-month period were recorded:

COMPANY PROGRAM 1.4 0.4 4.8 3.7 0.5 5.2 0.7 5.4
COMPETITOR'S PROGRAM 0.7 3.9 1.5 0.1 0.3 1.6 0.5 2.6

Use a suitable parametric test, with a 5% level of significance, to assess the company’s claim. Why will this be a 1-sided test? [Note that the data is not paired (matched) in this question]

what test and formula would I use for this question?