Question

A study measured the relationship between the size of a truck’s engine (in liters) and its fuel economy (in mpg). It found a correlation coefficient of -0.9187, and a scatterplot of the data appeared to be approximately linear.

Which of the statements below are true? Select
**all** that apply.

The correlation is strong, so even a small change in engine size is likely to impact fuel economy. |
||

In general, as engine size increases, fuel economy decreases. |
||

In general, as engine size decreases, fuel economy decreases. |
||

The correlation is not strong, so a small change in engine size will not necessarily impact fuel economy. |

Answer #1

A random sample of 15 weeks of sales (measured in $) and 15
weeks of advertising expenses (measured in $) was taken and the
sample correlation coefficient was found to be r = 0.80. Based on
this sample correlation coefficient we could state
That the percentage of the variation in sales that is shared
with the variation in advertising is about 80%.
That the percentage of the variation in sales that is shared
with the variation in advertising is about...

18. The relationship between forced expiratory volume (FEV),
which is measured in liters, and age, which is measured in years,
is evaluated in a random sample of 200 men between the ages of 20
and 60. A simple linear regression analysis is performed to predict
FEV from age. The Intercept (constant) = 8.0 and the Regression
coefficient (slope) for Age = 0.29.
a. Interpret the regression coefficient for age in words.
[PLEASE PROVIDE RATIONALE]
b. Interpret the intercept (constant) in...

Q3) In a difference of proportion test with alpha= .01, the
critical value for a one tailed lower test is/are:
A) -1.96 B) -1.645 and 1.645
C) -2.33 D) -1.28
Q4) If the test statistic for a small sample difference of means
test is t*=-2.15, we could reject the Null Hypothesis at alpha =.01
for a two tailed test with degrees of freedom equal to 20:
true or false
Q9) In a difference of MEans test there are two sources...

A local authority is going to study the relationship between the
size of household and the daily plastic usage consumed by them. The
results of a sampling given below in Table 5 indicate some values
of X (weight o plastic usage) and Y (the size of household).
Table 5: Weight of plastic usage (X) and size of household
(Y)
X
0.27
1.41
2.19
2.83
2.19
1.81
0.85
3.05
Y
2
3
3
6
4
2
1
5
i) From the...

As part of a study on stress and its effects on aging,
researchers measured telomere length in blood cells of healthy
premenopausal women with chronically ill children.
Here is a link to the data set.
Question: What is the correlation coefficient for
these variables? Calculate your answer using the function
=correl(array 1, array2) in microsoft excel. Answer to three
decimal places.
Years
Telomere Length
1
1.63
1
1.24
1
1.33
2
1.5
2
1.42
2
1.36
2
1.32
3
1.47...

How does the fuel consumption of a car change as its speed
increases? Here are data for a British Ford Escort. Speed is
measured in kilometers per hour, and fuel consumption is measured
in liters of gasoline used per 100 kilometers traveled. Speed Fuel
10 21.00 20 13.00 30 10.00 40 8.00 50 7.00 60 5.90 70 6.30 80 6.95
Speed Fuel 90 7.57 100 8.27 110 9.03 120 9.87 130 10.79 140 11.77
150 12.83
(a) Make a scatterplot....

Belmont and Marolla conducted a study on the relationship
between birth order, family size, and intelligence. The subjects
consisted of all Dutch men who reached the age of 19 between 1963
and 1966. These men were required by law to take the Dutch army
induction tests, including Raven’s intelligence test. The results
showed that for each family size, measured intelligence decreased
with birth order: first-borns did better than second-borns,
second-borns did better than third-borns, and so on. And for any...

Belmont and Marolla conducted a study on the relationship
between birth order, family size, and intelligence. The subjects
consisted of all Dutch men who reached the age of 19 between 1963
and 1966. These men were required by law to take the Dutch army
induction tests, including Raven’s intelligence test. The results
showed that for each family size, measured intelligence decreased
with birth order: first-borns did better than second-borns,
second-borns did better than third-borns, and so on. And for any...

9. A lot of corn grows in Iowa. For several years, farmers have
kept track of the amount of rainfall (in inches) and the amount of
corn produced (in bushels per acre). A strong and linear
relationship has been observed between these variables. When a
regression equation is constructed in order to predict amount of
corn produced based on rainfall, it is found that the equation has
an intercept of 89.54 and a slope of 0.13. We can conclude from...

TRUE OR FALSE:
1. The sampling distribution of (X-bar) is
always a normal distribution according to the Central limit
theorem.
4. If the sampled population is a normal distribution, then the
sampling distribution of (X-bar is normal only for a
large enough sample size.
5. If p=.8 and n=50, then we can conclude that the sampling
distribution of the proportions is approximately a normal
distribution.
8. Assuming the same level of significancea, as the
sample size increases, the critical t-value...

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