Practice final exam 1  (Page 3/3)

Combined with convenience sampling, what other sampling technique did Maria use?

• A simple random
• B systematic
• C cluster
• D stratified

How many students come to campus for classes 4 days a week?

• A 49
• B 25
• C 30
• D 13

What is the 60th percentile for the this data?

• A 2
• B 3
• C 4
• D 5

Construct a 95% Confidence Interval for the true population mean number of dependents of Reservists called to active duty to increase security at California airports.

• A (1.85, 2.32)
• B (1.80, 2.36)
• C (1.97, 2.46)
• D (1.92, 2.50)

The 95% confidence Interval above means:

• A 5% of Confidence Intervals constructed this way will not contain the true population aveage number of dependents.
• B We are 95% confident the true population mean number of dependents falls in the interval.
• C Both of the above answer choices are correct.
• D None of the above.

$\mathrm{X~}$ $U(4,\mathrm{10})$ . Find the 30th percentile.

• A 0.3000
• B 3
• C 5.8
• D 6.1

If $\mathrm{X~}$ $\mathrm{Exp}\left(\mathrm{0.8}\right)$ , then $P\left(\mathrm{x<\mu }\right)$ =

• A 0.3679
• B 0.4727
• C 0.6321
• D cannot be determined

The lifetime of a computer circuit board is normally distributed with a mean of 2500 hours and a standard deviation of 60 hours. What is the probability that a randomly chosen board will last at most 2560 hours?

• A 0.8413
• B 0.1587
• C 0.3461
• D 0.6539

A survey of 123 Reservists called to active duty as a result of the September 11, 2001, attacks was conducted to determine the proportion that were married. Eighty-six reported being married. Construct a 98% confidence interval for the true population proportion of reservists called to active duty that are married.

• A (0.6030, 0.7954)
• B (0.6181, 0.7802)
• C (0.5927, 0.8057)
• D (0.6312, 0.7672)

Winning times in 26 mile marathons run by world class runners average 145 minutes with a standard deviation of 14 minutes. A sample of the last 10 marathon winning times is collected.

Let $\overline{x}$ = mean winning times for 10 marathons.

The distribution for $\overline{x}$ is:

• A $N\left(145,\frac{14}{\sqrt{10}}\right)$
• B $N\left(145,14\right)$
• C $t_9$
• D $t_{10}$

Suppose that Phi Beta Kappa honors the top 1% of college and university seniors. Assume that grade point means (G.P.A.) at a certain college are normally distributed with a 2.5 mean and a standard deviation of 0.5. What would be the minimum G.P.A. needed to become a member of Phi Beta Kappa at that college?

• A 3.99
• B 1.34
• C 3.00
• D 3.66

What was the expected farm population (in millions of persons) for 1980?

• A 7.2
• B 5.1
• C 6.0
• D 8.0

In linear regression, which is the best possible SSE?

• A 13.46
• B 18.22
• C 24.05
• D 16.33

In regression analysis, if the correlation coefficient is close to 1 what can be said about the best fit line?

• A It is a horizontal line. Therefore, we can not use it.
• B There is a strong linear pattern. Therefore, it is most likely a good model to be used.
• C The coefficient correlation is close to the limit. Therefore, it is hard to make a decision.
• D We do not have the equation. Therefore, we can not say anything about it.

The distribution for the test is:

• A ${{\mathrm{Chi}}^2}_8$
• B ${{\mathrm{Chi}}^2}_3$
• C $t_{721}$
• D $N(0,1)$

The expected number of female who choose Finance is :

• A 37
• B 61
• C 60
• D 70

The p-value is 0.0127 and the level of significance is 0.05. The conclusion to the test is:

• A There is insufficient evidence to conclude that the choice of major and the gender of the student are not independent of each other.
• B There is sufficient evidence to conclude that the choice of major and the gender of the student are not independent of each other.
• C There is sufficient evidence to conclude that students find Economics very hard.
• D There is in sufficient evidence to conclude that more females prefer Administration than males.

An agency reported that the work force nationwide is composed of 10% professional, 10% clerical, 30% skilled, 15% service, and 35% semiskilled laborers. A random sample of 100 San Jose residents indicated 15 professional, 15 clerical, 40 skilled, 10 service, and 20 semiskilled laborers. At $\alpha$ = .10 does the work force in San Jose appear to be consistent with the agency report for the nation? Which kind of test is it?

• A ${\mathrm{Chi}}^2$ goodness of fit
• B ${\mathrm{Chi}}^2$ test of independence
• C Independent groups proportions
• D Unable to determine