Question

1. A 95% CI for a population mean is 44.1±4.88

.(a) Can you reject the null hypothesis that *?*=37 at
the 5% level? (Type: YES or NO or CANNOT TELL):

(b) Can you reject the null hypothesis that *?*=48 at the
5% level? (Type: YES or NO or CANNOT TELL):

(c) In general, you fail to reject the null hypothesis if
*?* is the confidence interval. (Type: IN or NOT IN) :

2 . A random sample of size *?* has been selected from a
normally distributed population whose standard deviation is
*?*. In hypothesis testing for the population mean, the
t-test should be used instead of the z-test if:

**A.** *?*>30 and *?* is
unknown

**B.** *?*<30 and *?* is known

**C.** both A and B are true

**D.** both A and B are false

In selecting the sample size to estimate the population
proportion *?*

, if we have no knowledge of even the approximate value of the
sample proportion *?*̂ , we:

**A.** let *?*̂ =0.50

**B.** take another sample and estimate
*?*̂

**C.** let *?*̂ =0.95

**D.** take two more samples and find the average of
their *?*̂

Answer #1

1.

95% CI for a population mean is (44.1 - 4.88 , 44.1 + 4.88)

(39.22, 48.98)

Since 37 does not lie in the 95% CI, we **reject**
the null hypothesis that *?*=37 . Answer is
**Yes**

Since 48 lie in the 95% CI, we **cannot**
**reject** the null hypothesis that *?*=37 .
Answer is **No**

In general, you fail to reject the null hypothesis if *?*
is **IN** the confidence interval.

2.

We use z test if:

- σ is known, and the sample size is at least 30 (for any population)
- σ is known, and the original population is normal (for any value of n)

The t-test should be used instead of the z-test if

**A.** *?*>30 and *?* is
unknown

3.

If we have no knowledge of even the approximate value of the
sample proportion *?*̂ , we:

**A.** let *?*̂ =0.50

so, as to estimate the largest sample size.

A 95% CI for a population mean is 30±3.22.
(a) Can you reject the
null hypothesis that μ=24 at the 5% level? (Type: YES or
NO or CANNOT TELL):
(b) Can you reject the
null hypothesis that μ=31 at the 5% level? (Type: YES or
NO or CANNOT TELL):
(c) In general, you
reject the null hypothesis if μ is the confidence
interval. (Type: IN or NOT IN)

1.Suppose you wish to test the null hypothesis that the mean of
a population is 100 versus the alternative that the mean is not
equal to 100. You then take a sample and calculate a sample of mean
of 90. Which of the following conclusions is correct?
a.
You should reject the null hypothesis
b.
You should not reject the null hypothesis
c.
You should reject the null if n > 30, otherwise do not
reject
d.You should accept the...

Bob claims that a population mean u=94. The value of the
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Bob claims that the population proportion of good lemons is
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the a(alpha symbol)=0.01 significance level. Report the final
result of the test.
Hint: answer is either a) reject the null hypothesis
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Ho

#1.
a. You do a hypothesis test and reject the null hypothesis at
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should be an inequality.
b.Can you tell from this information whether you would reject at
the α = .10 level? Explain.
c. Can you tell from this information whether you would reject
at the α = .01 level? Explain.
#2
a You do a hypothesis test and fail to reject the null
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a. the probability the null hypothesis is true.
b. the probability the null hypothesis is false.
c. the probability, assuming the null hypothesis is false, that
the test statistic will take a value at least as extreme as that
actually observed.
d. the probability, assuming the null hypothesis is true, that
the test statistic will take a value at least as extreme as that
actually observed.
2. The P-value...

1. A null hypothesis states that there is
A. No significant difference between a population parameter and
sample statistic.
B. A significant difference between a population parameter and
sample statistic.
C. The difference between the population parameter and sample
statistic is significant and can be attributed to sampling
error.
D. The difference between the population parameter and sample
statistic is insignificant and cannot be attributed to sampling
error.
E. None of the above
2. An alternative hypothesis states that there...

Consider the computer output below.
Two-Sample T-Test and CI
Sample
N
Mean
StDev
SE Mean
1
15
54.79
2.13
0.55
2
20
58.60
5.28
1.2
Difference = μ1-μ2
Estimate for difference: –3.91
95% upper bound for difference: ?
T-test of difference = 0 (vs <): T-value = -2.93
P-value = ?
DF = ?
(a) Fill in the missing values. Use lower and upper bounds for
the P-value. Suppose that the hypotheses are H0: μ1-μ2=0 versus H1:
μ1-μ2<0.
Enter your...

The 95% confidence interval for the population mean was
calculated based on a random sample with sample size of n=31 as (50
to 60). Calculate the outcome of a 2 sided alpha=0.05 test based on
the null hypothesis of H0: mean=55, and determine if:
A.We would reject the null hypothesis.
B. We would accept the null hypothesis.
C. We woudl fail to reject the null hypothesis.
D. Not enough information to decide.

1. Forum Description Describe a test of significance on the mean
of a population by stating 1. a population, 2. a quantitative
variable on that population, 3. the population standard deviation
of that variable (with units), 4. a null hypothesis, 5. an
alternative hypothesis, 6. an α-level, 7. a sample size, and 8. a
sample mean of that variable (with units). Find 9. the one-sample
z-statistic and either 10. reject or fail to reject the null
hypothesis. What does this...

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