COBA Core BUS 3265

For which of the following would a control chart for attributes not be appropriate? a) Number of nonfunctioning light bulbs b) Proportion of broken eggs in a carton c) Number of rotten apples d) Number of complaints issued e) Length of metal rods

Length of metal rods

The center line of a control chart represents what? a) Range b) Standard deviation c) Mean d) Mean divided by standard deviation e) Skewness

Mean

What measures the central tendency of a set of data?a) Coefficient of variation b) Variance c) Standard deviation d) Mean e) Range

Mean

Which measure of central tendency can be used for both numerical and categorical variables? a) Arithmetic mean. b) Median. c) Mode. d) Geometric mean.

Mode

In a right-skewed distribution a) the median equals the arithmetic mean. b) the median is less than the arithmetic mean. c) the median is greater than the arithmetic mean. d) none of the above.

the median is less than the arithmetic mean.

For a p-chart or c-chart, what is the implication of a negative value for the LCL? a) A calculation error must have occurred. b) The value of sigma must be reduced. c) The process has too many errors. d) The process is in a state of control. e) The LCL can effectively be rounded up to 0.

The LCL can effectively be rounded up to 0.

Which of the following is a continuous quantitative (numerical) variable? a)The color of a student's eyes b)The number of employees of an insurance company c)The amount of milk in a 2-liter carton. d)The number of gallons of milk sold at the local grocery store yesterday

The amount of milk in a 2-liter carton.

Which of the following is sensitive to extreme values?a) The median. b) The interquartile range. c) The arithmetic mean. d) The 1st quartile.

The arithmetic mean.

The power of a statistical test is a) the probability of not rejecting H0 when it is false. b) the probability of rejecting H0 when it is true. c) the probability of not rejecting H0 when it is true. d) the probability of rejecting H0 when it is false.

the probability of rejecting H0 when it is false.

The test for the equality of two population variances is based on a) the difference between the 2 sample variances. b) the ratio of the 2 sample variances. c) the difference between the 2 population variances. d) the difference between the sample variances divided by the difference between the sample means.

the ratio of the 2 sample variances.

What are the four most common control charts? a) x-bar, R, p, c b) x-bar, R, p, OC c) x-bar, R, c, OC d) x-bar, p, c, OC e) R, p, c, OC

x-bar, R, p, c

A Type I error is committed when a) you reject a null hypothesis that is true. b) you don't reject a null hypothesis that is true. c) you reject a null hypothesis that is false. d) you don't reject a null hypothesis that is false.

you reject a null hypothesis that is true.

The standard deviation is an example of what? a) Traditional statistical tools b) Fishbone diagramming c) Acceptance sampling d) Experimental design e) Statistical process control

Fishbone diagramming

53. How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: X = 52, S = 22. Give the null and alternative hypotheses to determine if the number of tissues used during a cold is less than 60. a)H0 : 60 and H1 : 60. b) H0 : 60 and H1 : 60. c)H0 : X 60 and H1 : X 60. d) H0 : X 52 and H1 : X 52.

H0 : 60 and H1 : 60

The Wall Street Journal recently published an article indicating differences in perception of sexual harassment on the job between men and women. The article claimed that women perceived the problem to be much more prevalent than did men. One question asked of both men and women was: "Do you think sexual harassment is a major problem in the American workplace?" 24% of the men compared to 62% of the women responded "Yes." Assuming W designates women's responses and M designates men's, what hypothesis should The Wall Street Journal test in order to show that its claim is true? a) H0: W M 0 versus H1: W M < 0 b) H0: W M 0 versus H1: W M > 0 c) H0: W M = 0 versus H1: W M 0 d) H0: W M 0 versus H1: W M = 0

H0: W M 0 versus H1: W M > 0

If the outcome of event A is not affected by event B, then events A and B are said to be a) mutually exclusive. b) independent. c) collectively exhaustive. d) None of the above.

independent

If event A and event B cannot occur at the same time, then events A and B are said to be a) mutually exclusive. b) independent. c) collectively exhaustive. d) None of the above.

mutually exclusive.

In testing a hypothesis using the x2 test, the theoretical frequencies are based on the a) null hypothesis. b) alternative hypothesis. c) normal distribution. d) None of the above.

null hypothesis.

What is a control chart that monitors the proportion of defects in a sample? a) x-bar chart b) R-chart c) p-chart d) c-chart e) OC chart

p-chart

Which of the following is not associated with descriptive statistics? a) mean b) standard deviation c) range d) proportion e) measure of the distribution of data

proportion

P-charts are used to measure: a) continuous variation b) intermittent random variation c) proportion of items in a sample that is defective d) the count of defective parts e) proportion of items in a sample that are good

proportion of items in a sample that is defective

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in a certain year in the past. Suppose a sample of 100 major league players was taken. What was the standard error for the sample mean salary? a) $0.012 million b) $0.12 million c) $12 million d) $1,200.0 million

$0.12 million

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 64 fish yields a mean of 3.4 pounds, what is probability of obtaining a sample mean this large or larger? a) 0.0001 b) 0.0013 c) 0.0228 d) 0.4987

0.0228

According to a survey of American households, the probability that the residents own 2 cars if annual household income is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. The probability that the residents of a household do not own 2 cars and have an income over $50,000 a year is: a) 0.12 b) 0.18 c) 0.22 d) 0.48

0.12

What is the probability of a Type I error for a control chart with limits set at 3 standard deviations from the mean? a) 0.00% b) 0.26% c) 4.56% d) 20.00% e) 50.00%

0.26%

If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomly selected college student will find a parking spot in the library parking lot in less than 3 minutes. a) 0.3551 b) 0.3085 c) 0.2674 d) 0.1915

0.3085

The employees of a company were surveyed on questions regarding their educational background (college degree or no college degree) and marital status (single or married). Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is married and has a college degree is: a) 0.0667 b) 0.567 c) 0.667 d) 0.833

0.567

The employees of a company were surveyed on questions regarding their educational background (college degree or no college degree) and marital status (single or married). Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is single or has a college degree is: a) 0.10 b) 0.25 c) 0.667 d) 0.733

0.733

If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomly selected college student will take between 2 and 4.5 minutes to find a parking spot in the library parking lot. a) 0.0919 b) 0.2255 c) 0.4938 d) 0.7745

0.7745

Referring to Scenario 2-5, if 100 calls were randomly sampled, how many calls lasted 15 minutes or longer? a) 10 b) 14 c) 26 d) 74

26

The A2 factor includes how many standard deviations of ranges? a) 1 b) 2 c) 3 d) 4 e) 6

3

Upper and lower control limits are usually set at how many standard deviations from the mean? a) 0.5 b) 1.0 c) 2.0 d) 3.0 e) 6.0

3.0

Six-sigma quality implies how many average defects per million? a) 3.4 b) 6 c) 2600 d) 3 e) 6

3.4

If we are testing for the difference between the means of 2 independent populations presuming equal variances with samples of n1 = 20 and n2 = 20, the number of degrees of freedom is equal to a) 39. b) 38. c) 19. d) 18.

38

The owner of a fish market determined that the mean weight for a catfish is 3.2 pounds with a standard deviation of 0.8 pound. A citation catfish should be one of the top 2% in weight. Assuming the weights of catfish are normally distributed, at what weight (in pounds) should the citation designation be established? a) 1.56 pounds b) 4.84 pounds c) 5.20 pounds d) 7.36 pounds

4.84 pounds

What is the width of each class? A) 1 minute B) 5 minutes c) 2% d) 100%

5 minutes

Referring to Scenario 2-5, if 1,000 calls were randomly sampled, how many calls lasted under 10 minutes? a) 220 b) 370 c) 410 d) 590

590

What process width is typically used when computing the process capability index Cp? a) 1 b) 2 c) 3 d) 4 e) 6

6

When testing for independence in a contingency table with 3 rows and 4 columns, there are degrees of freedom. A) 5 B)6 C) 7 D) 12

6

Thirty-six of the staff of 80 teachers at a local intermediate school are certified in Cardio- Pulmonary Resuscitation (CPR). In 180 days of school, about how many days can we expect that the teacher on bus duty will likely be certified in CPR? a) 5 days b) 45 days c) 65 days d) 81 days

81 days

For the standard normal distribution, how much confidence is provided within 2 standard deviations above and below the mean? a) 97.22% b) 95.44% c) 99.74% d) 99.87% e) 90.00%

95.44%

Assuming that data exhibit a normal distribution, control limits set at 3 standard deviations from the mean capture how much common variation? a) 50.00% b) 80.00% c) 95.44% d) 99.74% e) 99.99%

99.74%

You have collected data on the monthly seasonally adjusted civilian unemployment rate for the United States over a 10-year period. Which of the following is the best for presenting the data? a) A contingency table. b) A stem-and-leaf display c) A time-series plot. d) A side-by-side bar chart.

A time-series plot.

Causes of variation that can be identified and eliminated are called what? a) Random b) Assignable c) Identifiable d) Stochastic e) Common

Assignable

An OC curve is an example of what? a) Traditional statistical tools b) Fishbone diagramming c) Acceptance sampling d) Experimental design e) Statistical process control

Acceptance sampling

Researchers suspect that the average number of units earned per semester by college students is rising. A researcher at Calendula College wishes to estimate the number of units earned by students during the spring semester at Calendula. To do so, he randomly selects 100 student transcripts and records the number of units each student earned in the spring term. He found that the average number of semester units completed was 12.96 units per student. Identify the population of interest to the researcher. a)All Calendula College students. b)All college students. c)All Calendula College students enrolled in the spring. d)All college students enrolled in the spring.

All Calendula College students enrolled in the spring.

Most analysts focus on the cost of tuition as the way to measure the cost of a college education. But incidentals, such as textbook costs, are rarely considered. A researcher at Drummand University wishes to estimate the textbook costs of first-year students at Drummand. To do so, she monitored the textbook cost of 250 first-year students and found that their average textbook cost was $600 per semester. Identify the population of interest to the researcher. a)All Drummand University students. b)All college students. c)All first-year Drummand University students. d)The 250 students that were monitored.

All first-year Drummand University students.

The standard error of the mean a) is never larger than the standard deviation of the population. b) decreases as the sample size increases. c) measures the variability of the mean from sample to sample. d) All of the above.

All of the above.

In a perfectly symmetrical bell-shaped "normal" distribution a) the arithmetic mean equals the median. b) the median equals the mode. c)the arithmetic mean equals the mode. d) All the above.

All the above.

The probability that house sales will increase in the next 6 months is estimated to be 0.25. The probability that the interest rates on housing loans will go up in the same period is estimated to be The probability that house sales or interest rates will go up during the next 6 months is estimated to be 0.89. The events increase in house sales and no increase in house sales in the next 6 months are A) independent. B) mutually exclusive C) collectively exhaustive. D) Both (b) and (c)

Both (b) and (c)

If we wish to determine whether there is evidence that the proportion of items of interest is the same in group 1 as in group 2, the appropriate test to use is a) the Z test. b) the 2 test. c) Both a) and b). d) Neither of a) nor b).

Both a) and b).

On a control chart, what separates common from assignable causes of variation? a) x-bar lines b) Control limits c) Specification limits d) Production limits e) Mean divided by standard deviation

Control limits

Which of the following statements about the median is not true? a) It is more affected by extreme values than the arithmetic mean. b) It is a measure of central tendency. c) It is equal to Q2. d) It is equal to the mode in bell-shaped "normal" distributions.

It is equal to Q2.

Which of the following statistics is not a measure of central tendency? a) Arithmetic mean. b) Median. c) Mode. d) Q3.

Q3

What is a control chart that monitors changes in the dispersion or variability of a process? a) x-bar chart b) R-chart c) p-chart d) c-chart e) OC chart

R-chart

All processes will have what type of variation? a) Random b) Assignable c) Identifiable d) Stochastic e) Common

Random

What measures the difference between the largest and smallest observations in a set of data? a) Range b) Coefficient of variation c) Coefficient of kurtosis d) Coefficient of skewness e) Standard deviation

Range

What is the first step that should be taken if an observation falls below the lower control limit on a control chart? a) Recalibrate the machine b) Perform a new process capability study c) Try a larger standard deviation value d) Search for assignable causes e) Nothing—a low value is a "good" thing

Search for assignable causes

What measures symmetry of a distribution? a) Range b) Skewness c) Standard deviation d) Mean e) Variance

Skewness

Which of the following would imply that data observations are closely clustered around the mean? a) Small range and small standard deviation b) Small range and large standard deviation c) Large range and small standard deviation d) Large range and large standard deviation e) Neither range nor standard deviation has anything to do with "clustering."

Small range and small standard deviation

A c-chart is an example of what? a) Traditional statistical tools b) Fishbone diagramming c) Acceptance sampling d) Experimental design e) Statistical process control

Statistical process control

A p-chart is an example of what? a) Traditional statistical tools b) Fishbone diagramming c) Acceptance sampling d) Experimental design e) Statistical process control

Statistical process control

An x-bar chart is an example of what? a) Traditional statistical tools b) Fishbone diagramming c) Acceptance sampling d) Experimental design e) Statistical process control

Statistical process control

What technique answers the question of whether the process is functioning properly or not? a) Fishbone diagramming b) Acceptance sampling c) Statistical process control d) Scatter plotting e) Experimental design

Statistical process control

What is a distribution called when the same numbers of observations are below the mean as are above the mean? a) Proportional b) Equalized c) Wholly Uniform d) Balanced e) Symmetric

Symmetric

A study is under way in Yosemite National Forest to determine the adult height of American pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains 25,000 adult American pines. The study involves collecting heights from 250 randomly selected adult American pine trees and analyzing the results. Identify the population from which the study was sampled. a)The 250 randomly selected adult American pine trees. b)The 25,000 adult American pine trees in the forest. c)All the adult American pine trees taller than 60 feet. d)All American pine trees, of any age, in the forest.

The 25,000 adult American pine trees in the forest.

A study is under way in Yosemite National Forest to determine the adult height of American pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains 25,000 adult American pines. The study involves collecting heights from 250 randomly selected adult American pine trees and analyzing the results. Identify the sample in the study. a)The 250 randomly selected adult American pine trees. b)The 25,000 adult American pine trees in the forest. c)All the adult American pine trees taller than 60 feet. d)All American pine trees, of any age, in the forest.

The 250 randomly selected adult American pine trees.

Most analysts focus on the cost of tuition as the way to measure the cost of a college education. But incidentals, such as textbook costs, are rarely considered. A researcher at Drummand University wishes to estimate the textbook costs of first-year students at Drummand. To do so, she monitored the textbook cost of 250 first-year students and found that their average textbook cost was $600 per semester. Identify the sample in the study. a)All Drummand University students. b)All college students. c)All first-year Drummand University students. d)The 250 students that were monitored.

The 250 students that were monitored.

Which of the following would be an appropriate alternative hypothesis? a) The mean of a population is equal to 55. b) The mean of a sample is equal to 55. c) The mean of a population is greater than 55. d) The mean of a sample is greater than 55.

The mean of a population is greater than 55.

Which of the arithmetic mean, median, mode, and geometric mean are resistant measures of central tendency? a) The arithmetic mean and median only. b) The median and mode only. c) The mode and geometric mean only. d) The arithmetic mean and mode only.

The median and mode only.

Which of the following is a discrete quantitative (numerical) variable? a)The Dow Jones Industrial average b)The volume of water released from a dam c)The distance you drove yesterday. d)The number of employees of an insurance company

The number of employees of an insurance company

Which of the following would be an appropriate alternative hypothesis? a) The population proportion is less than 0.65. b) The sample proportion is less than 0.65. c) The population proportion is not less than 0.65. d) The sample proportion is not less than 0.65.

The population proportion is less than 0.65.

Which of the following would be an appropriate null hypothesis? a) The population proportion is less than 0.65. b) The sample proportion is less than 0.65. c) The population proportion is not less than 0.65. d) The sample proportion is no less than 0.65.

The population proportion is not less than 0.65.

Consider a p-chart measuring the percentage of defective light bulbs. If the LCL is .04 and a sample has 1% defects, what is the implication? a) The process is in a state of control. b) The process is out of control even though the variation is "good." c) The value of sigma must be increased. d) The process has too many errors. e) A calculation error must have occurred.

The process is out of control even though the variation is "good."

Which of the following is most likely a parameter as opposed to a statistic? a)The average score of the first five students completing an assignment. b)The proportion of females registered to vote in a county. c)The average height of people randomly selected from a database. d)The proportion of trucks stopped yesterday that were cited for bad brakes.

The proportion of females registered to vote in a county.

Which of the following statements is not true about the level of significance in a hypothesis test? a) The larger the level of significance, the more likely you are to reject the null hypothesis. b) The level of significance is the maximum risk we are willing to accept in making a Type I error. c) The significance level is also called the level. d) The significance level is another name for Type II error.

The significance level is another name for Type II error.

A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches. To test this claim against the alternative that the actual proportion of doctors who recommend aspirin is less than 0.90, a random sample of 100 doctors was selected. Suppose you reject the null hypothesis. What conclusion can you reach? A) There is not sufficient evidence that the proportion of doctors who recommend aspirin is not less than 0.90. B) There is sufficient evidence that the proportion of doctors who recommend aspirin is not less than 0.90. C) There is not sufficient evidence that the proportion of doctors who recommend aspirin is less than 0.90. D) There is sufficient evidence that the proportion of doctors who recommend aspirin is less than 0.90.

There is sufficient evidence that the proportion of doctors who recommend aspirin is less than 0.90.

What is the term for the probability that a value falling outside the control limits is still due to normal variation? a) Type I error b) Type II error c) Normalization anomaly d) Beta risk e) Standard deviation irregularity

Type I error

The different characteristics that can be measured by control charts can be divided into what two groups?a) Parameters and attributes b) Variables and attributes c) Variables and constraints d) Variables and parameters e) Attributes and constraints

Variables and attributes

An entrepreneur is considering the purchase of a coin-operated laundry. The current owner claims that over the past 5 years, the mean daily revenue was $675 with a population standard deviation of $75. A sample of 30 days reveals a daily mean revenue of $625. If you were to test the null hypothesis that the daily mean revenue was $675, which test would you use? a) Z-test of a population mean b) Z-test of a population proportion c) t-test of population mean d) t-test of a population proportion

Z-test of a population mean

The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the proportion of students at her university who visited campus bars on the weekend before the final exam week. Her assistant took a random sample of 250 students. The answer on "whether you visited campus bars on the weekend before the final exam week" from students in the sample is an example of a)a categorical variable. b)a discrete variable. c)a continuous variable. d)a table of random numbers.

a categorical variable.

Researchers are concerned that the weight of the average American school child is increasing implying, among other things, that children's clothing should be manufactured and marketed in larger sizes. If X is the weight of school children sampled in a nationwide study, then X is an example of a)a categorical variable. b)a discrete variable. c)a continuous variable. d)a table of random numbers.

a continuous variable.

To monitor campus security, the campus police office is taking a survey of the number of students in a parking lot each 30 minutes of a 24-hour period with the goal of determining when patrols of the lot would serve the most students. If X is the number of students in the lot each period of time, then X is an example of a)a categorical variable. b)a discrete variable. c)a continuous variable. d)a statistic.

a discrete variable.

The portion of the universe that has been selected for analysis is called a)a sample. b)a frame. c)a primary data source. d)a secondary data source.

a sample.

The standard error of the mean for a sample of 100 is 30. In order to cut the standard error of the mean to 15, we would a) increase the sample size to 200. b) increase the sample size to 400. c) decrease the sample size to 50. d) decrease the sample to 25.

increase the sample size to 400.

The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a Blu-ray player made by the company over the past 12 months are satisfied with their products. The population of interest is a)all the customers who have bought a Blu-ray player made by the company over the past 12 months. b)all the customers who have bought a Blu-ray player made by the company and brought it in for repair over the past 12 months. c)all the customers who have used a Blu-ray player over the past 12 months. d)all the customers who have ever bought a Blu-ray player made by the company.

all the customers who have bought a Blu-ray player made by the company over the past 12 months.

The standard error of the population proportion will become larger a) as population proportion approaches 0. b) as population proportion approaches 0.50. c) as population proportion approaches 1.00. d) as the sample size increases.

as population proportion approaches 0.50.

What type of probability distribution will most likely be used to analyze warranty repair needs on new cars in the following problem?The service manager for a new automobile dealership reviewed dealership records of the past 20 sales of new cars to determine the number of warranty repairs he will be called on to perform in the next 90 days. Corporate reports indicate that the probability any one of their new cars needs a warranty repair in the first 90 days is 0.05. The manager assumes that calls for warranty repair are independent of one another and is interested in predicting the number of warranty repairs he will be called on to perform in the next 90 days for this batch of 20 new cars sold. A) binomial distribution. B) Poisson distribution. C) Hypergeometric distribution. D) None of the above.

binomial distribution.

If either event A or event B must occur, then events A and B are said to be a) mutually exclusive. b) independent. c) collectively exhaustive. d) None of the above.

collectively exhaustive.

The Six Sigma approach is organized around a _______ plan known as ________. a) four step, PDAC b) four step, DMAC c) five step PDACR d) five step DMAIC e) five step, DMCRA

five step DMAIC

The Central Limit Theorem is important in statistics because a) for a large n, it says the population is approximately normal b) for any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size. c) for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population. d) for any sized sample, it says the sampling distribution of the sample mean is approximately normal.

for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population.

A process chart is a a) graph that shows how the population was evaluated b) graph of the population failures c) graph that shows whether a sample of data falls within assignable causes d) graph that show whether a sample falls within the common or normal range e) table showing final inspection results

graph that show whether a sample falls within the common or normal range

A completely randomized design a) has only one factor with several treatment groups. b) can have more than one factor, each with several treatment groups. c) has one factor and one block. d) has one factor and one block and multiple values.

has only one factor with several treatment groups.

Which of the following is most likely a population as opposed to a sample? a)respondents to a newspaper survey. b)the first 5 students completing an assignment. c)every third person to arrive at the bank. d)registered voters in a county.

registered voters in a county.

A selection of raffle tickets from a large bowl is an example of A) simple probability. B) sampling without replacement. C) subjective probability. D) None of the above.

sampling without replacement.

Sampling distributions describe the distribution of a) parameters. b) statistics. c) both parameters and statistics. d) neither parameters nor statistics.

statistics

What are the two aspects to implementing the six-sigma concept? a) numerically controlled machines and inventory management b) numerically controlled machines and people involvement c) numerically controlled machines and technical tools d) technical tools and people involvement e) inventory management and technical tools

technical tools and people involvement

A ___is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis. a) significance level b) critical value c) test statistic d) parameter

test statistic

In a perfectly symmetrical distribution A) the range equals the interquartile range. B) the interquartile range equals the arithmetic mean. C) the median equals the arithmetic mean. D) the variance equals the standard deviation.

the median equals the arithmetic mean.

Statistical process control tools are used most frequently because a) they are mathematically based b) they are helpful in measuring and evaluating the quality of products c) they are helpful in measuring and evaluating the customers' needs d) they are qualitative evaluation techniques e) they provide a definitive ROI calculation

they are helpful in measuring and evaluating the quality of products

If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic a) unbiased. b) minimum variance. c) biased. d) random.

unbiased

What is a control chart that monitors changes in the mean value of a process? a) x-bar chart b) R-chart c) p-chart d) c-chart e) OC chart

x-bar chart