Statistics and Probability Answers

A manufacturer of light bulbs produces bulbs that last a mean of 950 hours with a standard deviation of 120

hours. What is the probability that the mean lifetime of a random sample of 10 of these bulbs is less than 900

hours?

A. Find each of the following percentile points under the normal curve.

3. P74

4. P81

given population 2,7,9 what is the population variance

the curve of a normal distribution extends identify at the tails but does not touch it.this means that the curve is blank to the baseline

Verify that this [P(x)] is a probability distribution

In a case of 24 plates, 3 of the plates have defects. The first plate taken from the case is defective and not returned to the case. What is the probability that the next plate sold is not defective?

Directions: Find the corresponding area between z = 0 and eachof thefollowing z-value. Use separate sheet of paper for your answers. 1. z = 0.96 2. z =− 1.74 3. z = 2.18 4. z =− 2.69 5. z = 2.93

Let X be a random variable that is normally distributed with a mean of 10 and a

standard deviation of 2. Assume that a sample of 25 observations are taken from

this distribution, What is the interquartile range of the distribution of the sample

means.

The mean number of houses sold by a real estate agent per week is 2. Find the

probability that over the next 6 weeks, the real-estate agent sells between 5 and

12 houses (both inclusive).

Activity 2

1. In a Science test, the mean score is 42 and the standard deviation is 5.

Assuming the scores are normally distributed, what percent of the score is

a. Greater than 48?

b. Less than 50?

c. Between 30 and 48?

Sketch the normal

curve