Download agb 360 - agribusiness statistics

AGB 360 - AGRIBUSINESS STATISTICS
Multiple Choice Questions Below:
Question 1 1 points Save
A range of values constructed from sample data so that the population parameter occurs
within that range at a specified probability is
A. the population parameter.
B. the mean of the population
C. a confidence interval.
D. a point estimate.
Question 2 1 points Save
The probability that an interval estimates contains the value of the population parameter is
indicated by
A. the degrees of freedom.
B. the confidence level.
C. the precise value of the population mean U
D. the degrees of freedom minus 1.
Question 3 1 points Save
The width of a confidence interval is called the
A. the standard error
B. the sampling error
C. the margin of error
D. the error of confidence
Question 4 1 points Save
In general, higher confidence levels result in
A. wider confidence intervals
B. narrower confidence intervals
C. a smaller standard error
D. unbiased estimates
Question 5 1 points Save
All things being equal, as the sample size increases, the margin of error
A. widens
B. narrows
C. stays the same
D. None of the above
Question 6 1 points Save
The t distribution is a family of continuous distribution, with many similarities to
A. the confidence interval.
B. the population parameter.
C. the standard normal distribution.
D. the mean of the population.
Question 7 1 points Save
The t distribution is used when the population is normal, the population standard deviation is
unknown and
A. the sample contains less than 30 observations.
B. the population standard deviation is known.
C. the point estimate is known.
D. the mean of the population is unknown.
Question 8 1 points Save
The finite population correction factor may be used to adjust the margin of error of a C.I. for
the population mean or the margin of error of a C.I. for the population proportion when:
A. the sample constitutes more than 5% of the finite population.
B. the sample constitutes less than 5% of the finite population.
C. the sample is larger than the finite population.
D. the finite population cannot be estimated.
Question 9 1 points Save
The fraction, ratio, or percent indicating the part of the population having a particular trait of
interest is
A. a confidence interval.
B. the population mean.
C. the population proportion.
D. a point estimate.
Question 10 1 points Save
The distribution of the sample proportion is approximated by the normal distribution when:
A. n is less than 30.
B. (as in a binomial distribution) π is less than 5.
C. (as in a binomial distribution) Both nπ and n(1-π) are greater than 5.
D. Standard Deviation is given.
Question 11 1.5 points Save
In order to estimate the average time spent on the computer terminals per student at a local
university, data were collected for a sample of 81 business students over a one-week period
and the sample mean equals 9 hours. Assume the population standard deviation is 1.8 hours.
The 95% confidence interval for the average time spent on the computer at this university is:
A. 7.04 to 110.96 hours per week
B. 7.36 to 10.64 hours per week
C. 7.80 to 10.20 hours per week
D. 8.61 to 9.39 hours per week
Question 12 1 points Save
Situation 1: It is known that SAT scores are normally distributed. A "small" random sample
of 26 SAT scores of students applying for merit scholarships showed an average of 1400
with a standard deviation of 240. If we want to construct a 95% confidence interval for the
average SAT score of the population, the degrees of freedom for reading the critical values of
the "t" statistic is
A. 23
B. 24
C. 25
D. 26
Question 13 1.5 points Save
Refer to situation 1: The 95% confidence interval for the SAT scores is
A. 1340.06 to 1459.94
B. 1307.75 to 1492.5
C. 1303.04 to 1496.96
D. 1400 to 1600
Question 14 1.5 points Save
A random sample of 1000 registered voters was taken. Four hundred fifty of the people in
the sample favored Candidate P. Develop a 95% confidence interval of the population
proportion of registered voters who favor Candidate P
A. 0.419 to 0.481
B. 0.40 to 0.50
C. 0.45 to 0.55
D. 1.645 to 1.96
Question 15 1.5 points Save
An agribusiness temp-worker company needs to calculate a 95% confidence interval
estimate for the average daily number of workers that they hire. Assuming that the company
reports that the standard deviation is 200 temp-workers per day, how many days does the
firm needs to sample so that the margin of error of the 95% C.I. will be 39.2 temp-workers or
less?
A. need to have a sample size of at least 40 days
B. need to have a sample size of at least 100 days
C. need to have a sample size of at least 1000 days
D. None of the above
Question 16 1 points Save
An assumption made about the value of a population parameter is called a
A. conclusion
B. hypothesis
C. confidence
D. significance
Question 17 1 points Save
In hypothesis testing, the status quo, the state of nature, the "innocent until proven guilty"
assumption made about the value of the population parameter is
A. the alternative hypothesis.
B. the null hypothesis.
C. either the null or the alternative.
D. None of these alternatives is correct.
Question 18 1 points Save
In hypothesis testing, committing the error of rejecting a true null hypothesis is
A. a Type I error, denoted a
B. a Type II error, denoted B
C. Committed when not enough information is available.
D. None of the above.
Question 19 1 points Save
The level of significance of a hypotheses test is the
A. maximum allowable probability of committing a Type II error
B. maximum allowable probability of committing a Type I error
C. same as the confidence level
D. same as the p-value
Question 20 1 points Save
The p-value is a probability that measures the support (or lack of support) for the
A. null hypothesis
B. alternative hypothesis
C. sample statistic
D. None of the above
Question 21 1 points Save
When the p-value approach is used for hypothesis testing, the null hypothesis is rejected if
A. p-value < or = to a
B. a < p-value
C. p-value > or = to a
D. p-value = a
Question 22 1.5 points Save
Situation 2: Customers start to get upset after 3 minutes of waiting at the checkout and the
store looses money if too many cashiers are assigned. Therefore, management wants to
determine, at α = 0.05 level, whether or not the average waiting time of all customers is
significantly different than 3 minutes. The manager of a grocery store has taken a random
sample of 100 customers. The average length of time it took the customers in the sample to
check out was 3.1 minutes with a standard deviation of 0.5 minutes. The correct set of
hypotheses for the test is
A. Ho: u < 3
Ha: u < or equal to 3
B. Ho: = 3
Ha: does not equal 3
C. Ho: u does not equal 3
Ha: u does equal 3
D. Ho: u greater than or equal to 3
Ha: u < 3
Question 23 1.5 points Save
Refer to situation 2: Find the critical value for this test (hint: check α level and whether is a
one-tailed or two-tailed test)
A. 1.645
B. 1.96
C. 2.00
D. 0.056
Question 24 1.5 points Save
Refer to situation 2: Calculate the test statistic
A. 1.645
B. 1.96
C. 2.00
D. 0.056
Question 25 1.5 points Save
Refer to situation 2: Using the critical value approach, our conclusion is that the
A. average waiting time is significantly different than 3 minutes
B. average waiting time is not significantly different than 3 minutes
C. average waiting time is significantly less than 3
D. None of the above
Question 26 1.5 points Save
Situation 3: Evaluate the situation below. For a one-tailed test (upper tail) and a sample size
of 26 at the 5% significance level, the appropriate t critical value is
A. 1.706
B. -2.06
C. -1.708
D. 1.708
Question 27 1.5 points Save
Refer to situation 3: The test statistic is
A. 2.33
B. 1.955
C. -2.33
D. -1.955
Question 28 1.5 points Save
Refer to situation 3: Using the critical value approach, it can be concluded that the mean of
the population is
A. significantly greater than 20
B. not significantly greater than 20
C. significantly less than 20
D. None of the above
Question 29 1.5 points Save
Situation 4: We are interested in determining whether or not the proportion of the population
in favor of Candidate A is significantly greater than 80%.
Ho: π less than or equal to .80
Ha: π > .80
A random sample of 100 people was taken. Eighty-five of the people in the sample favored
Candidate A. The test statistic for this hypothesis of the population proportion equals
A. 0.80
B. 0.05
C. 1.25
D. 2.00
Question 30 1.5 points Save
Refer to situation 4: Based on the test statistic you just calculated, the p-value is
A. 0.2112
B. 0.05
C. 0.025
D. 0.1056
Question 31 1.5 points Save
Refer to situation 4: Based on the p-value you just calculated, at the α = 0.05 confidence
level, it can be concluded that the proportion of the population in favor of candidate A
A. the population proportion is significantly greater than 80%
B. the population proportion is not significantly greater than 80%
C. the population proportion is significantly greater than 85%
D. the population proportion is not significantly greater than 85%