Question

A manufacturer of cream filled donuts collected data from its automatic filling process. The amount of cream inserted into the donuts is normally distributed. To make sure that the automatic filling process is on​ target, quality control inspectors take a sample of 25 donuts. The correct value of t to construct a​ 90% confidence interval for the true mean amount of cream filling is​ _______.

Answer 1

The appropriate solution is "1.7109". A further explanation is provided below.

Explanation:

The given values are:

Sample size,

n = 25

Degree of freedom,

`df=n-1`

`=25-1`

`=24`

At 90% confidence level,

`\alpha=1-90 \ percent`

`=1-0.9`

`=0.1`

and,

`(\alpha)/(2)=(0.1)/(2)`

`=0.05`

Now,

The correct values of t will be:

=
`t_{(\alpha)/(2), df }`

=
`t_(0.05,24)`

=
`1.7109`