Statistics

Question 1

Statistics is to investigate some characteristics of a population by using a sample from it. T or F?

Answer 1

True

Question 2

A sample usually reflects the population perfectly. T or F?

Answer 2

False

Question 3

Statistics and probability theory refer to a same subject of study. T or F?

Answer 3

False

Question 4

Probability theory is ______.

Answer 4

A study of chances

Question 5

A key word of statisics is ______.

Answer 5

sample

Question 6

Statisics is synonymous with data processing. T or F?

Answer 6

False

Question 7

Probability theory is used in statistics to tell the possible error rate of extrapolating a sample to its population. T or F?

Answer 7

True

Question 8

In general, the _____ the sample size, the more accurate the sample reflects the population.

Answer 8

larger

Question 9

If sample size equals to population size, then ______.

Answer 9

the sample would perfectly reflect what the population is like

Question 10

It is always possible to have errors when we use a sample to tell what its population is like, unless the sample is the same as the population. T or F?

Answer 10

True

Question 11

Suppose the mean of a sample is 264.83. Where is the mean of the population?

Answer 11

We do not know

Question 12

If we select 100 samples from the same population, then the 100 sample means are typically different. T or F?

Answer 12

True

Question 13

If we select two samples from the same population, then the means of the two samples must be same. T or F?

Answer 13

False

Question 14

When we investigate the population mean from a sample, we can calculate the sample mean but we never know where the population mean exactly is. T or F?

Answer 14

True

Question 15

Suppose 95% of confidence interval for the population mean is (14.7, 20.5). It implies that there is _____ chance the population mean is within that range, and there is _____ chance the population mean is not in that range.

Answer 15

95%, 5%

Question 15

When we investigate the population mean from a sample, we figure out a range in which the population mean is likely located. T or F?

Answer 15

True

Question 16

If the confidence interval level for a confidence interbal is 98% then the error rate alpha is ______.

Answer 16

2%

Question 17

Suppose that sample mean is μ and the confidence interval for population mean is (μ-E, μ+E), where E=CONFIDENCE.T(α,σ,n). E will be getting smaller if: the sample size is getting ________.

Answer 17

larger

Question 18

Suppose that sample mean is μ and the confidence interval for population mean is (μ-E, μ+E), where E=CONFIDENCE.T(α,σ,n). E will be getting smaller if: the standard deviation of the data in the sample is _________.

Answer 18

smaller

Question 19

Suppose that sample mean is μ and the confidence interval for population mean is (μ-E, μ+E), where E=CONFIDENCE.T(α,σ,n). E will be getting smaller if: the allowed error rate α is _________.

Answer 19

larger

Question 20

Suppose that sample mean is μ and the confidence interval for population mean is (μ-E, μ+E), where E=CONFIDENCE.T(α,σ,n). E will be getting smaller if: the confidence level (1-α) is ______.

Answer 20

lower

Question 21

Suppose that sample mean is μ and the confidence interval for population mean is (μ-E, μ+E), where E=CONFIDENCE.T(α,σ,n). E will be getting smaller if: The 99% confidence interval is ______ than 95% confidence interval in a same problem.

Answer 21

larger

Question 22

Suppose the sample mean is 7.1, and the 95% confidence interval is (4.5, 9.7). The population mean must be in the range (4.5, 9.7). T or F?

Answer 22

False

Question 23

Suppose the sample mean is 7.1, and the 95% confidence interval is (4.5, 9.7). What is the probability of error if you say that the population mean is somewhere in the range (4.5, 9.7)?

Answer 23

0.05

Question 24

Suppose the sample mean is 7.1, and the 95% confidence interval is (4.5, 9.7). How sure is it that population mean is within (4.5, 9.7)?

Answer 24

With 95% of sureness

Question 25

Suppose the sample mean is 7.1, and the 95% confidence interval is (4.5, 9.7). Can you say that population mean is more than 5 with 95% of confidence?

Answer 25

No

Question 26

Suppose the sample mean is 7.1, and the 95% confidence interval is (4.5, 9.7). Can you say that population mean is more than 4 with 95% of confidence?

Answer 26

Yes