# statistics

posted by Sabrina

A test has a mean of 104 and a standard deviation of 16. We want to be 98% certain that we are within 4 points of the true mean. Determine the sample size.

1. MathGuru

Use a formula to find sample size.

Here is one:
n = [(z-value * sd)/E]^2
...where n = sample size, z-value will be found using a z-table to represent the 98% confidence interval, sd = 16, E = 4, ^2 means squared, and * means to multiply.

Plug the values into the formula and finish the calculation. Round your answer to the next highest whole number.

Hope this helps.

2. Toni

87

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