Question

Water Temperature If the variance of the water temperature in a lake is 24°, how many days should the researcher select to measure the temperature toestimate the true mean within 5° with 99% confidence? Round the intermediate calculations to two decimal places and round up your final answer to the nextwhole number The researcher needs a sample of at least ?days.

Answer 1

Since we have given that:

Variance = 24°

Standard deviation = √24 = 4.9

Mean = 5°

At 99% confidence, z value = 2.576

So, number of days that the researcher select to measure the temperature would be:

`n\text{ = (}(z*\sigma)/(\chi))^2\text{ = }(\frac{2.58\text{ }*\text{ }4.9}{5})^{2\text{ }}=\text{ }6.37`

Hence, the number of days would be 7 days.