What percentage of people made less than nine phone calls? (2 marks) Your Answer
What is the probability that a randomly chosen person from the sample made between 13 to 20 phone calls? (2 marks) Your Answer
Refer to the following diagram and then answer question 25.
A normally distributed variable has a Mean of 100 and a Standard Deviation of 15.
Fill in the Blanks with numerical values. (1 mark each = 6 marks total)
Your Answer
a. 68.3% of scores are between ___ and ___.
b. 95.5% of scores are between ___ and ___.
c. 99.7% of scores are between ___ and ___.
What is the probability of a normal random variable taking a value less than 1.8 SDs above its mean (rounded to one decimal)?
(3 marks)
Your Answer
What is the probability of a normal random variable taking a value less than 2.34 SDs below its mean (rounded to a whole number)? (3 marks)
Your Answer
What is the probability of a normal random variable taking a value more than 1.91 SDs above its mean (rounded to one decimal)? (3 marks)
Your Answer
Read the following scenario and then answer questions 29 -32.
The height of men in the UK is normally distributed with a mean of 177 cm and standard deviation of 12 cm.
What is the probability of a UK man being shorter than 145 cm (rounded to 2 decimals)? (3 marks) Your Answer
What is the probability of a UK man being taller than 195 cm (rounded to 1 decimal)? (3 marks)
Your Answer
If all UK men suddenly grew 5 cm in height, what would happen to the population mean? (3 marks)
a. It would become 172 cm
b. It would stay the same
c. It would become 177 cm
d. It would become 182 cm
e. Not enough information has been provided to answer this question
Your Answer
If all UK men suddenly grew 5 cm in height, what would happen to the population standard deviation? (3 marks)
a. It would become 5 cm
b. It would become 7 cm
c. It would stay the same
d. It would become 17 cm
e. Not enough information has been provided to answer this question
Your Answer
