Statistics and Probability Answers

5) In an experimental group of 250 individuals, half were given regular doses of aspirin while the other half were given placebos with no effects. Test the claim that the aspirin group has a significantly lower heart attack rate than the placebo group.

Calculate the Median and Mode from the following data:
Annual Sales(Rs.000) Frequency
Less than 10 4
Less than 20 20
Less than 30 35
Less than 40 55
Less than 50 62
Less than 60 67

A fair green die has faces numbered 6, 6, 8, 8, 11 and 11. Let X denotes the random variable that represents the score when the green die is rolled. Find the probability distribution for X.

Question 1
(a). A casino gambler keeps on inserting fifty Ghana
pesewa coins into a vending machine with the hope of
winning ten Ghana cedis after each try. After five tries,
he has not won anything. Nevertheless, he decides to
continue playing the game.
(i). Indicate whether the decision taken is right or wrong,
giving reasons for your answer.
(ii). Base on your decision taken in (i) above, explain the
probability concept that the gambler employed in
playing the game.
(b). In a coin tossing experiment, two error decisions are
likely to occur. Briefly discuss the implications of
making each of the two errors.

Question 4
From actual road tests with the tires, Hankook Tires estimated that
the mean tire mileage is 36,500 miles and that the standard
deviation is 5000 miles. Data is normally distributed.
(i) What percentage of the tires can be expected to last more
than 40,000 miles?
(ii) Assume that Hankook Tires is considering a guarantee
that will provide a discount on replacement tires if the
original tires do not provide the guaranteed mileage. What
should the guarantee mileage be if the company wants no
more than 10% of the tires to be eligible

All freshmen in a particular school were found to
have variability in grades expressed as a standard
deviation of 3. Two samples among these
freshmen, made up of 20 and 50 student’s each,
were found to have means of 88 and 85
respectively. Based on their grades, is the first
group really brighter than the second group at
£=0.01?

P(0.50<Z<1.04)

The mean IQ score for 2000 students is 100​, with a standard deviation of 10. Assuming the scores have a normal​ curve, answer the following.
a. How many have an IQ score between 90 and 110​?
b. How many have an IQ score between 80 and 120​?
c. How many have an IQ score over 130​?

Suppose you just received a shipment of 7 televisions. 4 of the televisions are defective. If two televisions are randomly​ selected, compute the probability that both televisions work. What is the probability at least one of the two televisions does not​ work?

1. The probability that both televisions work is ______