college

posted by .

The diameter of a wire should be 8 cm. It follows a normal distribution and has a standard deviation of 0.01 cm.
A person tests each delivery by taking 5 samples, accepting the goods only if the mean is at most 8.01

a)
Find the probability of type 1 error?

b)
A hypothesis test is to be carried out with P(type I error) = P(type II error) and either one being at 0.1%.
What is the necessary sample size for this test? (answer in my book says it's n=17)

2)
A company will sell a new product if the proportion of customers that will buy it is at least 20%. It is decided that the null hypothesis is rejected if the sample proportion is at least 27%. Sample size = 100.
a) Find P(type I error)

b)
If P(do not reject the null hypothesis)must be at least 99% if the true proportion is 0.17 and
P(reject the null hypothesis)must be at least 99% if the true proportion is 0.27:
which sample size is required?
(My book's answer is n = or greater than 365)

I don't understand how to solve these kind of questions, I'd greatly appreciate if you could help explain !

  • probability and statistics) -

    Help wanted in this subject

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math (Statistic)

    Considered the sampling distribution of a sample mean obtained by random sampling from an infinite population. This population has a distribution that is highly skewed toward the larger values. a) How is the mean of the sampling distribution …
  2. statistics

    The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 50 students who took the exam is selected for …
  3. stats

    Suppose the mass of college students can be modeled by the normal distribution. We believe the mean of the normal distribution is 72 kg. We randomly sample 18 students and find an average of 69 kg and a standard deviation of 4kg. A. …
  4. MATH

    Which of the following normal distributions has the smallest spread?
  5. Statistics

    1. The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 60 students who took the exam is selected for …
  6. Statistics

    This is the first question..... For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3. This is the second question....For each of the following samples …
  7. Math

    LongLast Inc. produces car batteries. The mean life of these batteries is 60 months. The distribution of the battery life closely follows the normal probability distribution with a standard deviation of 8 months. As part of its testing …
  8. Statistics

    The following is a histogram (right skewed) of the first ten terms of a geometric distribution with p = .4. The mean of this distribution is 2.5 and the standard deviation is approximately 1.93. What's the shape of the distribution …
  9. stats

    (a) The test had six multiple-choice items that were scored as correct or incorrect, so the total score was an integer between 0 and 6. Do you think that these data are Normally distributed?
  10. Statistics

    You are interested in estimating the mean of a population. you plan to take a random sample from the population and use the samples mean as an estimate of population mean. Assuming that the population from which you select your sample …

More Similar Questions