Question

The t value for a 99% confidence interval estimation based upon a sample of size 10 is

Answer 1

Answer:
For a sample size of 10, the t-value is about 3.25 (from tables) at a 99% confidence interval.

Explanation:
When the standard deviation for the population is not known, the confidence interval estimate for the population mean is performed with the Student's t-distribution.
The confidence interval for the mean is calculated as
$(\Bar{x}- t\frac{s}{\sqrt{n}} , \, \Bar{x}+ t\frac{s}{\sqrt{n}}$
where
 $\Bar{x}$ = sample mean,
s = sample standard deviation,
t = t-value (provided in tables),
n =  sample size.

When reading the t-value, (n-1) is called the df or degrees of freedom.