Dear all

Please help on below questions :

Kindly do not use Excel formulas

Thanks

Question 2

A company receives 4 enquiries per week relating to its new product, on average. Determine

the probability that the number of enquiries in any one week will be

(a) none

(b) two

(c) 3 or more

Question 3

(a) Three per cent of a certain product are rejects. For a production run of 400 determine the

mean and standard deviation of the probability distribution.

(b) Brass terminals are packed in boxes of 200. If the production process is known to produce

1.5 per cent defectives on average, determine the probability that a box chosen at random will

contain 2 defectives.

Question 4

A company is concerned about a low retention rate for employees. On the basis of past

experience, management has seen a turnover of 10% of the employees annually. Thus, for

any employee chosen at random, management estimates a probability of 0.1 that the person

will not be with the company next year.

Choosing 3 employees a random, determine the probability that 1 of them will leave the

company this year.

Compare your answer with a tree diagram.

Question 5

According to the United States Census Bureau, in 2000, 18.3% of all households have 3 or

more cars.

(a) In a simple random sample of 400 households, determine the mean and standard deviation

number of households that will have 3 or more cars.

(b) A researcher believes this percentage has increased since then. He conducts a simple

random sample of 400 households and found that 82 households had 3 or more cars. Is this

result unusual if the percentage of households with 3 or more cars is still 18.3%?

(c) A researcher believes this percentage has increased since then. He conducts a simple

random sample of 20 households and found that 5 households had 3 or more cars. Is this

result unusual if the percentage of households with 3 or more cars is still 18.3%?

(d) One year later, the same researcher conducts a simple random sample of 20 households

and found that 8 households had 3 or more cars. Is this result unusual if the percentage of

households with 3 or more cars is still 18.3%?

Question 6

In 1910, Ernest Rutherford and Hans Geiger recorded the number of -particles emitted from

a polonium source in eighth-minute (7.5 second) intervals. The results are reported in the

given table. Does a Poisson probability function accurately describe the number of -

particles emitted?