Use the appropriate formula to find the number of people that must be tested (round up to a whole numbe
A psychologist has developed a new test of spatial perception, and she wants to estimate the mean score achieved by male pilots. Complete the following steps to determine how many people must she test if she wants the sample mean to be in error by no more than ±4 points, with 98% confidence? An earlier study suggests that the standard deviation is 32.5.
(NOTE: All areas are to four decimal places and all z-scores are to two decimal places except the two special cases at the bottom of the table)
Insert the following values from the question:
CL = %
σ = points
E = points
What area relates to the confidence level?
A =
What is the value of α?
What is the value of α/2?
What area value will you use on the z-score table?
What is the zα/2 value associated with that area?
Use the appropriate formula to find the number of people that must be tested (round up to a whole number):
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