If the variance of the water temperature in a lake is 30°, how many days should the researcher select to measure the temperature to estimate the true mean within 4° with 95% confidence? Round the intermediate calculations to two decimal places and round up your final answer to the next whole number

The number of days would be 7 days.

Step-by-step explanation:

Since we have given that

Variance = 30°

Standard deviation = √30 =  5.47

Mean = 4°

At 95% confidence, z = 1.96

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

Hence, the number of days would be 7 days.

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.

asdsaddsa

step-by-step explanation: