P ( Z < − 2.49 )

Question

Assume that the readings at freezing on a batch of thermometers are normally distributed with a mean of 0°C and a standard deviation of 1.00°C. A single thermometer is randomly selected and tested. Find the probability of obtaining a reading less than -2.49°C. Round your answer to 4 decimal places

Answer 1

Given the distance from the mean of 0° is -2.49°, and division by the standard deviation of 1.00° gives a Z score of -2.49, the answer of P(Z<-2.49) is correct. As most, if not all, calculations of area under a portion of a normal distribution curve are done by a Z table or a calculator with the values for Z to decimal ratio internal to it, Which do you have available during your test, and what kind of calculator if you are allowed to use one?