Exam 5: Some Important Discrete Probability Distributions

The number of 000 calls in Hobart has a Poisson distribution with a mean of 10 calls a day.The probability of seven or eight 000 calls in a day is ______

A probability distribution is an equation that

A major retailer in Australia wishes to form a team of 16 executives from different departments within the company.Suppose the company has a total of 60 executives,and 20 of these are from the marketing department.If the members of the team are to be selected at random,what type of probability distribution can be used to figure out the probability that the team will contain four executives from the marketing department?

A covariance of zero shows that two variables X and Y are ______.

In a game called Taxation and Evasion,a player rolls a pair of dice.If on any turn the sum is 7,11 or 12,the player gets audited.Otherwise,she avoids taxes.Suppose a player takes five turns at rolling the dice. -The standard deviation of the number of times she will be audited is ______.

Instruction 5.1 The following table contains the probability distribution for X = the number of retransmissions necessary to successfully transmit a 1024K data package through a double satellite media. X 0 1 2 3 p(X) 0.35 0.35 0.25 0.05 -Referring to Instruction 5.1,the mean or expected value for the number of retransmissions is ______.

Instruction 5.8 From an inventory of 48 new cars being shipped to local dealerships, corporate reports indicate that 12 have defective radios installed. -Referring to Instruction 5.8,what is the probability out of the eight new cars it just received that,when each is tested,no more than half of the cars have non-defective radios?

Suppose that past history shows that 60% of university students prefer Brand C cola.A sample of five students is to be selected. -The probability that exactly three prefer Brand C is ______

The number of 000 calls in Hobart has a Poisson distribution with a mean of 10 calls a day.The probability of seven 000 calls in a day is ______

Instruction 5.3 There are two houses with almost identical characteristics available for investment in two different neighbourhoods with drastically different demographic composition. The anticipated gain in value when the houses are sold in 10 years has the following probability distribution: Returns Probability Neighbourhood A Neighbourhood B 0.25 -\ 22,500 \ 30,500 0.40 \ 10,000 \ 25,000 0.35 \ 40,500 \ 10,500 -Referring to Instruction 5.3,if your investment preference is to minimise the amount of risk that you have to take and do not care at all about the expected return,will you choose a portfolio that will consist of 10%,30%,50%,70% or 90% of your money on the house in neighbourhood A and the remaining on the house in neighbourhood B?

In a game called Taxation and Evasion,a player rolls a pair of dice.If on any turn the sum is 7,11 or 12,the player gets audited.Otherwise,she avoids taxes.Suppose a player takes five turns at rolling the dice. -The expected number of times she will be audited is ______.

Instruction 5.6 The quality control manager of Marilyn's Biscuits is inspecting a batch of chocolate chip biscuits. When the production process is in control, the average number of chocolate chip parts per biscuit is 6.0. -Referring to Instruction 5.6,what is the probability that any particular biscuit being inspected has 4.0 chip parts?

A stock analyst was provided with a list of 25 stocks.He was expected to pick three stocks from the list whose prices are expected to rise by more than 20% after 30 days.In reality,the prices of only five stocks would rise by more than 20% after 30 days.If he randomly selected three stocks from the list,he would use what type of probability distribution to compute the probability that all of the chosen stocks would appreciate more than 20% after 30 days?

Suppose that past history shows that 60% of university students prefer Brand C cola.A sample of five students is to be selected. -The probability that at most two prefer Brand C is ______.

In a binomial distribution

If X has a binomial distribution with n = 4 and p = 0.3,then P(X > 1.= ______

Instruction 5.8 From an inventory of 48 new cars being shipped to local dealerships, corporate reports indicate that 12 have defective radios installed. -Referring to Instruction 5.8,what is the probability out of the eight new cars it just received that,when each is tested,exactly half of the cars have defective radios?

Instruction 5.3 There are two houses with almost identical characteristics available for investment in two different neighbourhoods with drastically different demographic composition. The anticipated gain in value when the houses are sold in 10 years has the following probability distribution: Returns Probability Neighbourhood A Neighbourhood B 0.25 -\ 22,500 \ 30,500 0.40 \ 10,000 \ 25,000 0.35 \ 40,500 \ 10,500 -Referring to Instruction 5.3,if you can invest 70% of your money on the house in neighbourhood A and the remaining on the house in neighbourhood B,what is the portfolio expected return of your investment?

The standard deviation of a discrete random variable is the square root of the______

A national trend predicts that women will account for half of all business travellers in the next 3 years.To attract these women business travellers,hotels are providing more amenities that women particularly like.A recent survey of Australian hotels found that 70% offer hairdryers in the bathrooms.Consider a random and independent sample of 20 hotels.Find the probability all of the hotels in the sample offered hairdryers in the bathrooms.