$X$ is normally distributed with $P (X < 20) = 0.2$ and $P (X > 32) = 0.1$ . What is the standard deviation of $X$ , to $3$ significant figures?

Practise more Statistics and probability.

Free questions with an explanation for every one, and full timed IB Diploma mock tests.

All Statistics and probability questions Take a mock test

More Statistics and probability questions

The mean of five numbers is $24$ . Four of the numbers are $20, 22, 27, 26$ . What is the fifth number?
The mean of five numbers is $28$ . Four of the numbers are $23, 29, 24, 30$ . What is the fifth number?
The mean of five numbers is $23$ . Four of the numbers are $18, 28, 26, 26$ . What is the fifth number?
The mean of five numbers is $25$ . Four of the numbers are $19, 29, 21, 22$ . What is the fifth number?
The mean of five numbers is $15$ . Four of the numbers are $12, 9, 11, 16$ . What is the fifth number?
The mean of five numbers is $28$ . Four of the numbers are $32, 29, 33, 27$ . What is the fifth number?