Question

(CO6) Determine the minimum sample size required when you want to be 75% confident that the sample mean is within fifteen units of the population mean. Assume a population standard deviation of 327.8 in a normally distributed population

1293

785

632

1835

(CO6) Market research indicates that a new product has the potential to make the company an additional $3.8 million, with a standard deviation of $1.7 million. If this estimate was based on a sample of 10 customers from a normally distributed data set, what would be the 90% confidence interval?

(2.81, 4.79)

(2.11, 5.56)

(2.76, 4.84)

(3.06, 4.54)

Answer 1

We have given:

C = 0.75 , = 327.8 , E = 15

We know that sample size n = [ (Z_0.75 * ) / E]²

= [ (1.15 * 327.8) / 15 ]²

= 631.97

   632 (Rounded to next whole integer)

Hence the required sample size n = 632

Hope this will help you. Thank you :)