Samples from two independent, normally-distributed populations produced the following results.

population 1 population 2
sample size 7 9
sample mean 15.9 12.6
sample standard deviation 10.2 13.4

calculate the 95% confidence interval for the difference between population means μ1-μ2

a. 1.889
b. 8.6
c. 1.128
d. 1.286

The 95% confidence interval for the difference between population means μ1-μ2 is .

Step-by-step explanation:

Given : Samples from two independent, normally-distributed populations produced the following results.

                                     Population 1                 Population 2

Sample size                            7                                   9

Sample mean                        15.9                              12.6

Sample standard deviation 10.2                              13.4

The confidence interval for the difference between population means μ1-μ2 is given by :-

, where = sample size from population 1

 = sample size from population 2

= Difference between sample mean of two population

= Sample standard deviation of population 1.

= Sample standard deviation of population 2.

t* = Critical value for and significance .

As per given :

df = 7+9-2=14

Critical t-value :

So , the 95% confidence interval for the difference between population means μ1-μ2 would be

Hence, the 95% confidence interval for the difference between population means μ1-μ2 :