Statistics and Probability Answers

A sample of size 3 is to be selected from a population of 10 households. List all
possible samples by linear systematic sampling.

From the list of 500 names and addresses, 100 names are selected without
replacement and 25 wrong addresses were found. Identify the population and
estimate the total no. of addresses needing correction in the list. Also estimate the
standard error of the estimate.

A bag contains 10 white and 3 black balls. Balls are drawn one by one without
replacement till all the black balls are drawn. Find the probability that this
procedure come to an end at the 6th draw.

I was looking at the answer for question # 30740 and am wondering if it is right. The formula states n-1 = 24. The sample size in this question is 20, so wouldn't n-1 = 19? If that is true, would the correct answer be 1.729?

Thank you!

Fred is answering a multiple choice question exam. Each question has n possible answers. If Fred knows the correct answer to a question, he always gets it correct; otherwise he takes a guess, picking any answer with equal probability.

Let K be the event that Fred knows the answer to a question and let R be the event that Fred answers the question correctly. Given P(K) = 3 what is P(R)?

Senior management of a consulting services firm is concerned about a growing decline in the firm’s weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviewing the records of all the firm’s full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 90% confidence interval for the standard deviation of the number of hours this firm’s employees spend on work-related activities in a typical week.

23,17,29,36,15,6,18,24,32,41,14,27,33,18,24

Calculate the mean deviation.

A product is sold in a tin. The weight of the product is 500grams with a standard deviation of 5 grams; the weight of the tin is 100 grams with a standard deviation of 2 grams.

Find the probability that the contents of the tin will weigh:

(a) less than 495 grams
(b) more than 512 grams
(c) between 495 grams and 512 grams

Find the probability that the tin and the contents will weigh:

(d) less than 595 grams
(e) exceed 610 grams

A dealer marks his goods at 20% above the price he pays, but allows a customer a discount of
5% of the marked price of the goods. Find:

(i) the price that a customer pays for goods marked $646 (4 marks)

(ii) the price that customer pays for goods that cost the dealer $880 (3 marks)

(iii) the cost to the dealer for goods for which a customer paid $280.44 (3 marks)

(a) A company produces and sells television sets at RM 350 each. The company’s fixed costs
per annum are as follows:
RM
Rent 3,040
Heating and lighting 2,760
Salaries 14,000
Advertising 900

The variable costs are RM 120 per television set. Using calculation method, find;

(i) the break-even point, (4 marks)

(ii) the loss when output is 70, (3 marks)

(iii) the profit when output is 300. (3 marks)