Chapter 8 AP Stats

A different species of cockroach has weights that are approximately Normally distributed with a mean of 50 grams. After measuring the weights of many of these cockroaches, a lab assistant reports that 14% of the cockroaches weigh more than 55 grams. Based on this report, what is the approximate standard deviation of weight for this species of cockroaches?

• 4.6

• 5.0

• 6.2

• 4.0

• Cannot determine without more information

With a mean of 62 and standard deviation of 11

what is the probability of a value that is AT MOST 70

Round your answer to the nearest ten thousandth

Find the z-score

x = 36 μ= 42 σ = 5

• 0.74

• 1.2

• -1.2

• 1.03

Find the z-score

x = 19 μ= 14 σ = 2.1

Type in your answer to the nearest hundredth

If the mean is 100 and the standard deviation is 5

What is the probability of having a value between 72 & 102?

• 0.3448

• 0.6554

• 0.0854

• 0.7132

If the mean if 100 and the standard deviation is 5

What is the probability of a value that is AT LEAST 95.

Type your answer to the nearest ten thousandth place

What is the probability of a score between 44 & 59?

Type your answer to the nearest ten-thousandth

On a standard normal curve, what is the probability of a value between -2.34 and -0.39?

• 0.4539

• 0.27.05

• 0.6409

• 0.3386

On a standard normal curve, what is the probability of a value LESS than 1.36?

Type your answer to the ten thousandth place.

On a standard normal curve, what is the probability of a number being AT LEAST -2.15?

Type your answer to the ten thousandth place.