Q1. Find the mean, variance, and standard deviation of the random variable having the probability distribution given in the following table. (Round your answers to four decimal places.)

Random variable, x	-9	-8	-7	-6	-5
P(X = x)	0.14	0.16	0.38	0.12	0.2

mean = ?

variance = ?

standard deviation = ?

Q2. A probability distribution has a mean of 40 and a standard deviation of 2. Use Chebyshev's inequality to find the minimum probability that an outcome is between 35 and 45.

(Round your answer to four decimal places.)

Q3. During a 5-week period in 2007, the stock of an insurance company and the stock of a small tech company showed the following weekly percentage changes.

Company	Weekly Price Change (%)
Insurance Stock	1.3	0.3	0.5	-0.9	0.7
Tech Stock	5	-0.4	-0.2	-2.7	-1.5

Find the variance of the weekly price changes of each. (Round your answers to four decimal places.)

Part A.

Insurance stock = ?

Tech Stock = ?

Part B

Relate the two variances found to the riskiness of the two stocks. ( which options below )

• No statement about the riskiness of these stocks can be made.
• The tech stock is riskier.
• The two stocks have the same riskiness.
• The insurance stock is riskier.