A quality control inspector must estimate the proportion of defective microcomputer chips coming from two different...

A quality control inspector must estimate the proportion of defective microcomputer chips coming from two different assembly operations. She knows that, among the chips in the lot to be inspected, 60% are from assembly operation A and 40% are from assembly operation B. In a SRS of 100 chips, 38 turn out be from operation A and 62 from operation B. Among the sampled chips from operation A, six are defective. Among the sampled chips from operation B, ten are defective.

(a) Considering only the SRS of 100 chips, estimate the proportion of defectives in the lot, and provide a 95% confidence interval.

(b) Stratifying the sample, after selection, into chips from operation A and B, estimate the proportion of defectives in the population, and estimate the standard error. Ignore the finite population correction in both cases. Which answers do you find more acceptable?

Solutions

Expert Solution

orchestra answered 1 year ago

Next > < Previous

Related Solutions

A quality control inspector must estimate the proportion of defective microcomputer chips coming from two different...

A quality control inspector must estimate the proportion of defective microcomputer chips coming from two different assembly operations. She knows that, among the chips in the lot to be inspected, 60% are from assembly operation A and 40% are from assembly operation B. Therefore, she takes a stratified random sample of 100 chips where 50 are randomly sampled from each operation. Among the sampled chips from operation A, six are defective. Among the sampled chips from operation B, ten are...

A quality control engineer is interested in estimating the proportion of defective items coming off a...

A quality control engineer is interested in estimating the proportion of defective items coming off a production line. In a sample of 255 items, 45 are defective. Calculate a 95.0% confidence interval estimate for the proportion of defectives from this production line. (Use 3 decimal places in calculations and in reporting your answers.) Lower Limit: Upper Limit:

20% of all CDs manufactured by an electronics company are defective. A quality control inspector randomly...

20% of all CDs manufactured by an electronics company are defective. A quality control inspector randomly selects 6 CDs from the production line. Use binomial distribution, what is the probability that more than 2 but less than 6 are defectives.

The quality-control inspector of a production plant will reject a batch of syringes if two or...

The quality-control inspector of a production plant will reject a batch of syringes if two or more defective syringes are found in a random sample of nine syringes taken from the batch. Suppose the batch contains 1% defective syringes. (a) Make a histogram showing the probabilities of r = 0, 1, 2, 3, , 8 and 9 defective syringes in a random sample of nine syringes. (b) Find μ. What is the expected number of defective syringes the inspector will...

A production process is checked periodically by a quality control inspector. The inspector selects simple random...

A production process is checked periodically by a quality control inspector. The inspector selects simple random samples of 50 finished products and computes the sample mean product weights x. If test results over a long period of time show that 5% of the x values are over 4.1 pounds and 5% are under 3.9 pounds, what is the standard deviation (in lb) for the population of products produced with this process? (Round your answer for the standard deviation to two...

A quality inspector is worrying about the defective produced in the production process. He wants to...

A quality inspector is worrying about the defective produced in the production process. He wants to test that the average defectives produced are 145 or less. He collects a sample of 25 production runs and found that a sample mean of 150 defectives were produced with a std deviation of 20. With this information he wishes to perform a hypothesis test at 5% significance level. The decision is to: Reject Null; test statistic < critical value (or t test statistic...

Out of six computer chips, two are defective. If two of the chips are chosen randomly...

Out of six computer chips, two are defective. If two of the chips are chosen randomly for testing, compute the probability that both of them are defective. List all the outcomes in the sample space, if we were checking all six computer chips. A quiz consists of 6 multiple-choice questions. Each question has 4 possible answers. A student is unprepared, and he has no choice but to guess answers completely at random. He passes the quiz if he gets at...

n chips manufactured, two of which are defective. k chips randomly selected from n for testing....

n chips manufactured, two of which are defective. k chips randomly selected from n for testing. Q1. What is Pr(a defective chip is in k selected chips) ? n persons at a party throw hats in a pile, select at random. Q2. What is Pr(no one gets own hat) ? Q3. Plot Pr (no one gets own hat) in the Y-axis and n=[1,1000] in the X-axis (~pmf)

An inspector is doing a quality control assessment on a new shipment of wireless headphones. The...

An inspector is doing a quality control assessment on a new shipment of wireless headphones. The original invoices for the headphones show 35% of their supply is from the Jabra company and 65% is from the Samsung company. The inspector also knows that Jabra’s headphones have a 3% defect rate (meaning that 3% of the sample will fail on first usage). The defect rate for Samsung headphones is estimated at 4%. Complete each subquestion that follows, showing all of your...

A process considered to be in control measures an ingredient in ounces. A quality inspector took...

A process considered to be in control measures an ingredient in ounces. A quality inspector took 10 samples, each with 5 observations as follows: Samples Observations 1 2 3 4 5 1 10 9 10 9 12 2 9 9 11 11 10 3 13 9 10 10 9 4 10 10 11 10 10 5 12 10 9 11 10 6 10 10 8 12 9 7 10 11 10 8 9 8 13 10 8 10 8 9...

Subjects