# Thread: Statistic Practice Question Help

1. ## Statistic Practice Question Help

A few questions on my practice exam for the exam on Monday morning, help if you can please!
Question 1:
The results of a provincial exam are normally distributed with a standard deviation of 6.54%. If 10% of students scored below 55% on the exam, find the value of the mean.

Question 2:
Rich breaks the speed limit 70% of the time. What is the probability that he will break the speed limit exactly 8 times in the next 10 trips? Express answer the nearest hundredth.

Again thank you for all the help and support!

2. ## Re: Statistic Practice Question Help

For Question 1:
$\frac{55-m}{6.54} = z(0.1)$,
where m is the mean you want to compute, z(0.1) is the 0.1 quantile of the standard normal, you can look it up in a table.
This is easily solved for m.

Question 2:
This is the binomial probability for p=0.7, k=8, and n=10.

Hope this helps,
Bart