Daytime high temperatures in New York in February are normally distributed with an average of 30.2º and a standard deviation of 8.5º.
Estimate the probability that the temperature on a given day in February is 22º or lower.

Question

Daytime high temperatures in New York in February are normally distributed with an average of 30.2º and a standard deviation of 8.5º.
Estimate the probability that the temperature on a given day in February is 22º or lower.

perl · Answer

You change the 22 degrees to a z score first, then use a z table to find the probability.

mrnood · Answer

It says "estimate"

22 deg is very close to 1 SD below the  mean

What is the probability of a sample < 1sd below the mean?

use the 68,95, 97.5 rule as a very good "estimate"

perl · Answer

here is a diagram of the empirical rule http://prntscr.com/7awm4v

mrnood · Answer

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