Question

1) The red blood cells counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382.

Find the probability that a randomly selected woman has a red blood cell count that is lower than 4.2.

(Results are rounded to 4 decimal places)

a) 0.1618

b)  0.8382

c)  0.3382

d) 0.7979

2) A KRC research poll asked respondents if they felt vulnerable to identity theft. Of 1002 people polled, 531 said "yes".

Find a 95% confidence interval for the proportion of people who felt vulnerable to identity theft.

(Results are rounded to 4 decimal places)

a)  (0.5034, 0.5564)

b)  (0.4990, 0.5608)

c)   (0.4769, 0.5829)

d)   (0.5041, 0.5559)

Answer 1

Solution: 1) The red blood cells counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382.

Find the probability that a randomly selected woman has a red blood cell count that is lower than 4.2.

Answer: a) 0.1618

Explanation:

We are given:

We have to find

Using the z score formula, we have:

  

  

  

Now, we have to find

Using the standard normal table, we have:

Therefore, the option a) 0.1618 is correct

2) A KRC research poll asked respondents if they felt vulnerable to identity theft. Of 1002 people polled, 531 said "yes". Find a 95% confidence interval for the proportion of people who felt vulnerable to identify theft.

Answer: b)

Explanation:

The 95% confidence interval for the proportion of people who felt vulnerable to identify theft is:

Where:

is the critical value at 0.05 significance level.

  

Therefore, the option b) is correct