Question

What sample size is necessary such that a 98% confidence interval for the mean, using σ = 3, has a width of pm±0.5?

Answer 1

Answer:

n = 195

Step-by-step explanation:

What sample size is necessary such that a 98% confidence interval for the mean, using σ = 3, has a width of pm±0.5?

We solve using Margin of error formula

= z × Standard deviation/√n

Margin of error = ± 0.5

Standard deviation = 3

n = ??

z = 2.326

Hence,

±0.5 = 2.326 × 3/√n

Cross Multiply

±0.5 × √n = 6.978

√n = 6.978/±0.5

√n = ±13.956

Square both sides

n = (±13.956)²

n = 194.769936

Approximately = 195 samples