Question

You want to estimate the mean time college students spend watching online videos each day. The estimate must be within 2 minutes of the population mean. Determine the required sample size to construct a 99% confidence interval for the population mean. Assume that the population standard deviation is 4.4 minutes. Leave as an integer.

Answer #1

Solution :

Given that,

standard deviation =s = =4.4

Margin of error = E =2

At 99% confidence level the z is,

= 1 - 99%

= 1 - 0.99 = 0.01

/2 = 0.005

Z/2 = 2.576

sample size = n = [Z/2* / E] 2

n = ( 2.576* 4.4 / 2 )2

n =32 rounded

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