Question

Assume that the thermometer readings are normally distributed with a mean of 0 degrees C and a standard deviation of 1.00 degrees C. A thermometer is randomly selected and tested. The probability of getting a reading between -1.39 degrees C and 1.69 degrees C is ____

Answer 1

Do you know how to get the z-scores for -1.39 and 1.69 from the formula:
\[\large z=\frac{X-\mu}{\sigma}\]

Answer 2

The main thing that I am stuck on is how to get the sigma

Answer 3

Sigma is the standard deviation, which is given as 1 degree C.

Answer 4

Ok, so would I use this formula to obtain the probability of the reading?

Answer 5

You need to find the two values of z-score and then use a standard normal distribution table to work out the required value of probability.