A random sample of size n = 80 is taken from a population with mean μ = -15.2 and standard deviation σ = 5.
What is the probability that the sample mean falls between -15 and -14? (Do not round intermediate calculations. If you use the z table, round "z" values to 2 decimal places. Round your final answer to 4 decimal places.
Solution :
= / n = 5 / 80 = 0.5590
= P[(-15 - (-15.2)) / 0.5590 < ( - ) / < (-14 - (-15.2)) / 0.5590)]
= P(0.3578 < Z < 2.1467)
= P(Z < 2.1467) - P(Z < 0.3578)
= 0.9841 - 0.6398
= 0.3443
Probability = 0.3443
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