please answer this ASAP

Question

The average monthly rainfall in Southern Ontario is 26 mm. If rainfall data over the year is normally distributed with a standard deviation of 3.8 mm. Calculate the probability that it will rain less than 30 mm. Show all your work and include a sketch for the z-scores.

Answer 1

Arshiyan

You want the area under the graph of the standard normal to the left of X=30

X=30, Z = (30-26) / 3.8 = 1.053

So find the Z score in the table closest to 1.053, then read off the area in the table. This will be your required probability. (exercise for you). As your data is given to 2 significant figures, you should quote your final answer to the same accuracy.

As for the sketch, sketch a normal distribution with mean 26, draw the line X=30 vertically and write Z=1.053 under X=30.

Mike