1. a) State two main criteria of discrete variable. Hence, give two examples of
ID: 2923336 • Letter: 1
Question
1. a) State two main criteria of discrete variable. Hence, give two examples of discrete variable.
b) Categorical data can be further classified into nominal and ordinal data. Briefly discuss nominal data by providing two examples of nominal data.
2. The records of patients at a children’s hospital are maintained by a physician who wants to know the relationship between the ages and heights of boys who are patients. The data for seven randomly selected boys is shown in the following table.
Age to the nearest year 13 11 11 6 9 7 10
Height in inches 62 56 58 46 51 50 54
a) Find r and r2. Interpret your findings. (12 marks)
b) Find the equation linear regression line. What can you suggest about the slope? Estimate the height of a boy patient who is 12 years old.
3. A) In an air pollution study, an experimental station obtained a mean of 2.36 micrograms of suspended benzene-soluble organic matter per cubic meter with a standard deviation of 0.48 from a random sample of size 10.
i. Construct a 99% confidence interval for the mean of the population. (4 marks)
ii. What sample size will reduce the margin of error to no greater than 0.03? (3 marks)
iii. What will be the effect on margin of error and a 99% confidence interval for mean population if the confidence interval level changed from 99% to 95%? (5 marks)
B) A random sample of 50 cans of peach halves has a mean weight of 16.1 ounces and a standard deviation of 0.4 ounce.
i. Construct a 90% confidence interval for the mean of the population. (4 marks)
ii. What will be the effect on margin of error and a 90% confidence interval for mean population if the standard deviation changed from 0.4 ounce to 0.45 ounce?
Explanation / Answer
Example:
Number of sibling in a family (since it is certain value, it cannot be 2.3 siblings)
Attendance at work on a Monday
Example:
Gender of the first year class
Type of pets in Canada
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