1.

store has recorded customer sales ($) for a sample of recent sales, summarised in the following table:

Class	Frequency
(0, 150]	3
(150, 300]	2
(300, 450]	24
(450, 600]	18
(600, 750]	12
(750, 900]	36
(900, 1050]	3

How many customers spent less than or equal to $300?

2.

Here is a sample of data:

2

5

4

8

What is the value of the mean?

Give your answer correctly rounded to two decimal places.

3.

Let X be the discrete random variable of cash prizes available. The following table shows the discrete probability distribution of the possible cash prizes available to players, with the corresponding probabilities.

X	P(X)
0	0.60
16	0.30
750	0.10

What is the expected value of the cash prize?

Please give your answer correctly rounded to two decimal places.

Do NOT include units in your answer.

Answer:

4.

Suppose that a random variable X is normally distributed with mean 100 and standard deviation 7.

What value of X has 2.5% of all values below it?

Please give your answer correctly rounded to two decimal places.

5.

A researcher found, that in a random sample of 106 people, 87 stated that they owned a laptop. What is the estimated standard error of the sampling distribution of the sample proportion?

Please give your answer correctly rounded to two decimal places.

With this calculation, only round at the final answer.