# Question

Refer to Example 5.4. Suppose an estimate of s is given by σ = 5 .75
a. If the level of confidence remains 99% but the desired width of the interval is reduced to 0.3, what is the necessary sample size?
b. If the level of confidence is reduced to 95% but the desired width of the interval remains 0.5, what is the necessary sample size?
c. If the level of confidence is increased to 99.5% but the desired width of the interval remains 0.5, what is the necessary sample size?
d. Describe the impact on the value of the sample size of increases (decreases) in the level of confidence for a fixed desired width.
e. Describe the impact on the value of the sample size of increases (decreases) in the desired width for a fixed level of confidence.

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