Using the standard normal table, the sum of the probabilities to the right of z = 2.18 and to the left of z = -1.75 is ________.

(a)

0.4854

(b)

0.4599

(c)

0.0146

(d)

0.0547

The time until first failure of a brand of inkjet printers is normally distributed with a mean of 1,500 hours and a standard deviation of 200 hours. What proportion of printers fails before 1000 hours?

(a)

0.0062

(b)

0.0668

(c)

0.8413

(d)

0.0228

Monthly expenditure on their credit cards, by credit card holders from a certain bank, follows a normal distribution with a mean of  Rs. 1,295.00 and a standard deviation of Rs. 750.00. What proportion of credit card holders spend more than Rs. 1,500.00 on their credit cards per month?

(a)

0.487

(b)

0.392

(c)

0.500

(d)

0.791

Let z be a standard normal variable. If the area to the right of z is 0.8413, then the value of z must be: ________.

(a)

1.00

(b)

-1.00

(c)

0.00

(d)

-0.41

If the area to the left of a value of z (z has a standard normal distribution) is 0.0793, what is the value of z?

(a)

-1.41

(b)

1.41

(c)

-2.25

(d)

2.25