# Project #90560 - statistics

Please include the steps on how to get the answers. Thank you.

1) The sampling distribution of the mean describes

a) the entire population

b) the entire sample

c) all sample means that could occur just by chance

d) the sampled distribution.

2) The standard error of thr mean serves as a rough indicator of the average amount by which sample meas deviate from

a) the population mean

b) each other

c) some population characteristic

d) the one observed sample mean

3) When sample size is suficiently large, about _____ percent of all sample means are within one standard error of the ssampling distribution mean.

a) 50

b) 68

c) 95

d) 100

4) Given that the population standard deviation equals 40 and that the sample consists of 25 observations, the standard error of the mean equals

a) 0.80

b) 5

c) 8

d) 40

5) A random sample of 100 college student is taken from the student body of a large university. Assume that, in fact, a population mean of 20 hours and a standard deviation of 15 hours describe the weekly study estimates for the entire student body. Therefore, the sampling distribution of the mean has a mean that

A) approximates 20 hours

B) equals 20 hours

C) lies within a couple of hours of 20

D) equals the one observed sample mean

6) A random sample of 100 college students is taken from the student body of a large university. Assume that, in fact, the population mean of 20 hours in a population standard deviation of 15 hours describe the weekly study estimates for the entire student body. About 95 percent the sample means in the sampling distribution should be between approximately

A) 18 and 20 hours

B) 18 and 22 hours

C) 17 and 23 hours

D) 15 and 25 hours

7) when testing a hypothesis, rejection regions are located in the

A) Extreme areas of the hypothesized sampling distribution

B) middle areas of the hypothesized sampling distribution

C) most sensitive areas of the hypothesized sampling distribution

D) most questionable areas of the hypothesized sampling distribution

8) the null hypothesis

A) is tested indirectly

B) makes a claim about a range of values

C) usually asserts that nothing special is happening with respect to some population characteristic

D) Usually is identified with the research hypothesis

9) the null hypothesis

A) supports the researcher's hypothesis

C) reflects the true state of affairs

D) reflects the truth most of the time

10) the alternative hypothesis

A) is the opposite of the no hypothesis

B) specifies a range of possible values

C) usually is identified with the research hypothesis

D) is described by all of the above

11) A decision to reject the null hypothesis implies that

A) there is a lack of support for the alternative hypothesis

B) there is support for the alternative hypothesis

C) the sample is probably not representative

D) the sample size is probably inadequate

12) critical z scores separate

A) true and false hypothesis

B) valid and invalid samples

C) common and rare outcomes

D) correct and incorrect decisions

13) the level of significance indicates the

A) proportion of probable outcomes

B) importance of the statistical analysis

C) probability that a correct decision has been made

D) degree of rarity required to reject the null hypothesis

14) Reject the no hypothesis if the observed z

A) deviates too far into the tails of the sampling distribution

B) appears to originate from the middle of the sampling distribution z

C) approaching a value of zero

D) differs from zero

15) strong support for the research hypothesis occurs whenever the null hypothesis is

A) retained

B) rejected

C) tested with a very large sample size

D) stated precisely

16) (note: this question requires Greek letters) investigator is concerned only about detecting the possibility that the mean IQ for a population of high school students is smaller than 100. Therefore, the alternative hypothesis should take the form

A) u = 100

B) u = 100

c) u > 100

D) u > 100

17) (Note: this question requires Greek letters) a standardized test of reading comprehension is designed to yield a value of 6.0 of sixth-graders are progressing as expected. And hope of accelerating their reading comprehension, a random sample of 36 sixth graders undergo an enriched reading program and attain an means score of 6.4. The appropriate statistical hypothesis are:

A) H0: u <= 6.0

H1: u > 6.0

b) H0: u = 6.0

H1: u not = 6.0

c) H0: u <= 6.4

H1: u > 6.4

d) H0: = 6.4

H1: not = 6.4

18) Point estimates suffer from a basic deficiency--They tend to be

A) biased

B) inaccurate

C) difficult to interpret

D) imprecise

19) given a sample mean of 130 and a sample standard deviation of 20, a point estimate of the unknown population mean would equal

A) 130

B) 130/20

C) 130 plus or minus 20

D approximately 90 to 170

20) although many different confidence levels have been used, the two most prevalent levels are

A) 90 and 95 percent

B) 90 and 99 percent

C) 95 and 99 percent

D) 99 and 99.9 percent

21) in an experiment to determine whether TV cartoons produce more aggressive behavior in grade school children, The no hypothesis states that TV cartoons have

A) an effect on aggressive behavior

B) at least a slight effect on aggressive behavior

C) no effect on her aggressive behavior

D) At most a weak effect on aggressive behavior

22) the Glen Valley steel company manufactures steel bars. If production is working properly, it turns out steel bars with a mean length of 2.8 feet with a standard deviation of 0.2 foot. Longer steel bars can be adjusted, but shorter steel bars must be scraped. You select a sample of 25 steel bars, and the mean length is 2.73 feet

At 0.05 level of significance, can you conclude the mean length of the steel bar is 2.8 feet?

State the null hypothesis and alternative hypothesis in WORDS. also state your conclusion in WORDS after you complete the hypothesis testing.

23) you are the manager of a restaurant for a fast food franchise. Last month the mean waiting time at the drive-through window was 3.7 minutes. The franchise helped you institute a new process intended to reduce waiting time. You select a random sample of 64 orders. The sample mean waiting time is 3.57 minutes minutes with a sample standard deviation of 0.8 minute.

At 0.05 level of significance, is the evidence that the population mean waiting time is less than 3.7 minutes?

State the null hypothesis and alternative hypothesis in WORDS. Also State your conclusion in WORDS after you complete the hypothesis testing.

24) the manager of a paint supply store wants to estimate the actual amount of paint contained in 1 gallon cans purchased from a nationally known manufacturer. It is known from the manufacturer's specification the standard deviation of the amount of paint is equal to 0.2 gallons. A random sample of 50 cans is selected, And the sample mean is 0.995 gallon.

Construct a 95% and a 99% confidence interval estimates of the population mean amount of paint included in a gallon can.

 Subject General Due By (Pacific Time) 11/03/2015 05:00 pm
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