Question

1: Tests of a new tire developed by a tire manufacturer led to an estimated mean tread life of 67,350 miles and standard deviation of 1,120 miles. The manufacturer will advertise the lifetime of the tire (for example, a “50,000 mile tire”) using the largest value for which it is expected that 98% of the tires will last at least that long. Assuming tire life is normally distributed, find that advertised value. Round your answer to two decimal places and do not give units.

2:

Draw a standard normal curve and shade appropriately to find the given probabilities (areas under curve). Match appropriately to answer the questions about what your picture should show you.

Question 1 options:

	P(z > 0.67)
	P(z < 2.36)
	P(-2.78 < z < 1.97)
	P(0 < z < 2.11)

Answer choices: please match them and explain how to do it.

1.	area to the left and is roughly less than half the curve so under 0.5
2.	area to the left and is roughly more than half the curve so over 0.5
3.	area to the right and is roughly less than half the curve so under 0.5
4.	area to the right and is roughly more than half the curve so over 0.5
5.	area in between and is roughly less than half the curve so under 0.5
6.	area in between and is roughly more than half the curve so over 0.5

Answer 1