To estimate the average students scores in a

Ответ:

Bamaboy8804

01.01.2022

The lower limit for a 98% confidence interval for the population mean is 79.40.

Step-by-step explanation:

Given : To estimate the average students' scores in a standardize test, a sample of 35 scores yielded a mean of 80 and a standard deviation of 9.

To find : What is a lower limit for a 98% confidence interval for the population mean?

Solution :

The confidence interval formula is given by,

$CI=\bar{x}\pm Z_c(\frac{\sigma}{n})$

The lower limit is $CI=\bar{x}-Z_c(\frac{\sigma}{n})$

Where, $\bar{x}=80$ is the mean

$\sigma=9$ is the standard deviation

n=35 is the number of element

Z_c at 98% is 2.33.

Substitute all values in the formula,

$CI=80-(2.33)(\frac{9}{35})$

CI=80-(2.33)(0.257)

CI=80-0.59881

CI=79.40

Therefore, The lower limit for a 98% confidence interval for the population mean is 79.40.

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