Answer:
1. Point estimate Md = 2
2. The 90% confidence interval for the difference between means is (1.01, 2.99).
3. The 95% confidence interval for the difference between means is (0.82, 3.18).
Step-by-step explanation:
a) The point estimate of the difference between the two population means is the difference between sample means:
2. We have to calculate a 90% confidence interval for the difference between means.
The sample 1, of size n1=50 has a mean of 13.6 and a standard deviation of 2.2.
The sample 2, of size n2=35 has a mean of 11.6 and a standard deviation of 3.
The estimated standard error of the difference between means is computed using the formula:
The degrees of freedom for this confidence interval are:
The critical t-value for a 90% confidence interval is t=1.663.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 90% confidence interval for the difference between means is (1.01, 2.99).
2. We have to calculate a 95% confidence interval for the difference between means.
The critical t-value for a 95% confidence interval and 83 degrees of freedom is t=1.989.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 95% confidence interval for the difference between means is (0.82, 3.18).