Question 2

Given SAT scores are approximately normally distributed with a mean of 1000 and standard deviation of 25, the proportion of people with SAT scores above 1049 is:

(a) 95%

(b) 5%

(c) 68%

(d) 2.5%

Question 3

Failing to reject the null hypothesis when it is false is called:

(a) Beta

(b) Alpha

(c) Type I Error

(d) Type II Error

Question 4

The probability of Messi scoring a goal in a match at La Liga is 65%. Assuming a Binomial model, what is the probability that Messi scores in 3 of the next 5 matches?

(a) 60%

(b) 18.11%

(c) 30%

(d) 33.6%

Question 5

The P-value for a right-tailed test is p=0.034. Which of the following is correct?

(a) The p-value for a left-tailed test based on the same sample would be p=-0.034

(b) We would reject the null hypothesis at the significance level at 5% but not at 1%

(c) The p-value for a two-tailed test based on the same sample would be p=0.060

(d) We would reject the null hypothesis at the significance level at 1% but not at 5%

Question 6

At a college, the probability that a student studies statistics and business in the same semester is 0.05. The probability that a student takes statistics is 0.25. The probability that a student is studying business, given that she is studying statistics is:

(a) 20%

(b) 25%

(c) 5

(d) 40%

Question 7

For any data set, we can ascertain that half of the observations are less than the

(a) Mode

(b) Standard Deviation

(c) Median

(d) Mean

Question 8

A sample of 200 light bulbs manufactured by Phelps Ltd found that 24 had a defect. A 95% confidence interval for the proportion of all Phelps light bulbs with a defect is 0.032 to 0.091. Which of the statements below best describe the correct interpretation of the confidence interval.

(a) If a large number of samples are drawn for the proportion of light bulbs with defect and a confidence interval is constructed, 95% of these intervals would contain the proportion of light bulbs with defect.

(b) Any random sample of size 200 will have a proportion of 0.091 of defect bulbs.

(c) None of the above

(d) The probability that the proportion of light bulbs with defect is between 0.032 and 0.091 is 95%.

Question 9

A coffee machine can be adjusted to deliver any xed number of millilitres of coffee. If the machine is operating with a standard deviation in delivery equal to 1.3 millilitres, what should be the mean setting so that a 12-millilitre cup will overow less than 5% of the time? Assume a normal distribution for millilitres delivered.

(a) 10.70 millilitres

(b) 13.30 millilitres

(c) 14.05 millilitres

(d) 9.95 millilitres