Search & Filtering
A marketing research analyst selects a random sample of ten customers out of the fourty
who purchased a particular item from central store. The ten customers purchased different item
from central store i.e. 11, 37, 25, 62, 51, 21, 18, 41, 32, 20. If a random sample of ten items are
selected, what is the probability that customer will have a mean item which is a) at least thirty
one b) at most fifty five c) between thirty nine and fifty six d) mean item is fifty percent and e)
mean item is hundred percent.
b) ) From the following variables, Categories them and also write a reason?
Number of children per family, Watch, Age, length of hair, Willing, weight of a box, love, height of
a tree, color of Shirts, life of a person, interest, hate, Speedo meter, number of citizens of a
country, employee performance, behavior, temperature, life of bulb.
The following data have been collected for a sample from a normal population: 5, 10, 8, 11,
17, 6, 15, 23, (a) What is the point estimate of population mean and standard deviation? (b) What
is the confidence interval for population mean at 99 per cent confidence interval?
Suppose that two machines I and II in a factory operate independently of each other. Past experience showed that during a given 8-hour time, machine I remains inoperative one third of the time and machine II does so about one fourth of the time. What is the probability that at least one of the machines will become inoperative during the given period
It is claimed that the average monthly income of chemical engineers last year was P27,900. A random
sample of 35 chemical engineers is selected and it is found out that the average monthly salary is P28,000.
Using 0.01 level of significance, can it be concluded that there is an increase in the average monthly income
of chemical engineers? Assume that the population standard deviation is P250.50.
a leading medical journal claims that 39% of young adults play organized sports. a physician wants to conduct a survey to verify this with her young adult patients and wants to do so with a margin error of (ME) of +-5%. what minimum sample size, rounded to the nearest whole person, does the physician need to use?
Question 3 A software Company has just won a contract worth GH¢80m, if it delivers a successful product on time, but only GH¢40m, if this is late. It faces a problem of whether to produce the work in-house or to subcontract.
To subcontract the work would cost GH¢20m but based on past experience would have only a 90% chance of being successful. In the event of the software not being successful , there would be insufficient time to re-write the whole package internally but there would still be the options of either a late-rejection of the contract (at a further cost of GH¢10m) or a late subcontracting of the work on the same terms as before. With this late start, the local subcontractor is estimated to have only a 50 / 50 chance of producing it late. In this case, the subcontractor still has to be paid GH¢50m, regardless of whether he meets the deadline or not.
i) Calculate expected values as appropriate. iii) Recommend a course of action to the company, with reasons.
Suppose that for a given computer salesperson, the probability distribution of
X= the number of systems sold in 1 week
Is given by the following:
X =1 P(x) =0.05 X= 2 P(x) = 0.10 X= 3 P(x)= 0.12 X= 4 P(x)=0.30 X= 5 P(x)= 0.30 X=6 P(x)= 0.11 X=7 P(x)= 0.01 X= 8 P(x)= 0.01
a. Find the mean value of x
A local television station sells 15-second 30-second and 60-second advertising spots. Consider the random variable x= length of a randomly selected commercial appearing on this station, and suppose that the probability of distribution of x given by the following table.
X 15 P(x) 0.1
X 30 P(x) 0.3
X 60 P(x) 0.6
What is the mean length for commercials appearing on this station?
Suppose you are rolling a die for 4 times.
Let x be the random variable finding how many times you will get a ‘3’.
a. List all possible values for x.
b. Find the probability distribution of x.
Find the value of c for which P(x < c) = 0.7.
