Statistics and Probability Answers

Find the area under the standard normal curve to the left of z = 1.31

Kp cafeteria is ver popular. On average, it sold 10 cups of coffee per hour. Find the probability that in an hour more than 3 cups of coffee are sold.

1. You read that a statistical test at the α = 0.01 level has probability 0.18 of making a Type II error when a specific alternative is true. What is the power of the test against this alternative?
2. You read that a statistical test at the α = 0.01 level has probability 0.14 of making a Type II error when a specific alternative is true. What is the power of the test against this alternative?

If I have 5 ten sided dice, what is the probability that all of them will show numbers 1-7? What about only 4? What about only 3, or 2, or 1, or none?

Precision park a co Ltd by shares is a job shop that specialises i n electric motor shafts. the average shaft for the E300 elctric motor is 0.55cm with the standard deviation of 0.10cm. it is normally distributed.
1. What is the probability that a shaft selected at random would be between 0.55cm and 0.65cm.
2. What is the probability that the shaft size will be greater than 0.65cm
3. What is the probability that the shaft size would be between 0.53cm and 059cm.
4. What is the probability that the shaft size would be under 0.45cm

If 2 cards are drawn from a normal deck of 52 cards, what is the probability that both cards will be spades?

A certain student has missed several weeks of class. This same student takes an exam comprised of 10 multiple choice questions. Each multiple choice question has 5 different choices. Assume further that this student has no knowledge of the material and takes a wild guess on each question.
What is the variance for how many he will get correct on this exam?

The mean lifespan of the insect is 144 days and the standard deviation of its lifespan is 16 days. Find the probability that the next insect studied lives:
a) Less than 140 days
b)More than 156 days

During production in a cement plant, test cubes of cement are taken at regular intervals and their compressive strengths, in kg m-2, determined. Analysis of data over a long time has shown that the compressive strength of these samples is normally distributed with a mean 0.0468 kg m-2 and a standard deviation 1.6 × 10-3 kgm-2.
Calculate the probability that a randomly chosen sample has a compressive strength below 0.045 kg m-2.

A major television network is trying to determine whether to increase or decrease the number of news based shows. They did a national survey and found that their population watched 8 shows per week. I need to determine if the mean number of news shows watched in my neighborhood is similar to the national mean.
My mean for my neighborhood is 10.

Question: How did you think that your sample would compare to the national mean? This is your hypothesis. State either the alternate or null hypothesis and identify which one you are stating.
Answer:
Question: Based on your hypothesis, would you use a one-tailed or two-tailed test? Explain why.
Answer:
Question: Remember that your sample was very small at 3. With a sample of 3, your degrees of freedom would be 2. Imagine you could have sampled many more people in your neighborhood. Post the number of people you would really want to sample if you could. Consider this your ideal N.
Answer:
Question: Imagine that you had your ideal N. Your alpha level was .05. Choose a one or two-tailed test as appropriate, and look up the critical value of t. State the value in your post.
Answer:
Question: What would you conclude about your neighborhood's news-watching behavior as compared to the national average if your obtained t was larger than your critical t value, and what you conclude if your obtained t was smaller than your critical value?