A random sample of 15 employees was selected. The average age in the sample was 31 years with a variance of 49 years. Assuming ages are normally distributed, the 98% confidence interval for the population average age is .

Assuming ages are normally distributed, the 98% confidence interval for the population average age is [26.3, 35.7].

Step-by-step explanation:

We have to construct a 98% confidence interval for the mean.

The information we have is:

- Sample mean: 31

- Variance: 49

- Sample size: 15

- The age is normally distributed.

We know that the degrees of freedom are

Then, the t-value for a 98% CI is t=2.625 (according to the t-table).

The standard deviation can be estimated from the variance as:

The margin of error is:

Then, the CI can be constructed as:

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,

the answer to your question is b.