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Suppose a normal distribution has a mean of 79 and a standard deviation of 7. What is P(x > or = to 86)?

User Huff
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2 Answers

2 votes

if it is P(x<=86) the answer is 0.84

Explanation:

User Marat Faskhiev
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4 votes

Answer:

P(X >= 86) = P (Z >= 1) = 0.1587 from the Z-scores table

Explanation:

Hopefully this time I will not make an algebraic mistake.

Ok

so mean u = 79, and standard dev = s = 7

We want P(X >= 86)

Standardize:

P ( (X - u)/s >= (86 - 79)/7 ) = P (Z >= 1) = 0.1587 from the Z-scores table

User J Whitfield
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