The following random sample of weekly student expenses in dollars is obtained from a normally distributed population of undergraduate students with unknown parameters.
8 |
56 |
76 |
75 |
62 |
81 |
72 |
69 |
91 |
84 |
49 |
75 |
69 |
59 |
70 |
53 |
65 |
78 |
71 |
87 |
71 |
74 |
69 |
65 |
64 |
You have been charged to conduct a statistical test in SPSS to verify the claim that the‘average weekly student expenses’ is different than 74 dollars using an alpha level of 5%.
What is the appropriate test that is applicable in this case. Explain your reasoning.
State the null and alternate hypotheses in this case using proper statistical notations.
List one assumption that you are making about the distribution.
Insert a copy of the summary table of descriptive statistics generated in SPSS.
Insert a copy of the table for the statistical test you conducted in SPSS.
Drawing on information from the tables in (e) and/or (f) show how they relate to t-statistic as obtained in SPSS.
What is/are the critical value(s) of the test statistic at the 5% significance level.
What can you conclude about the claim based on the results generated from the statistical test? Make sure to support your conclusion by referencing the appropriate statistics from the test.
Compute the 90% confidence interval for the average weekly expenses.
Compute the Cohen’s d effect size.
In: Math
It's tough to find out how much people earn, but in 2011, a magazine reported that the average lawyer's salary in a country was $64,000. Suppose that today you interview a random sample of 55 lawyers in the country and find that the average salary is $75,275, with a standard deviation of $82,694.Do you think the average lawyer's salary today is higher than that reported by the magazine in 2011? For this problem, assume alphaαequals=0.05.
Let muμ be the population mean lawyer's salary in the country.
Determine the null and alternative hypotheses.
H0 : u = 64,000
HA : u > 64,000
Test statistic is 1.01
What is the P-Value?
In: Math
Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$45,783, $57,017]. The population standard deviation used for the analysis is known to be $13,700. [You may find it useful to reference the z table.]
a. What is the point estimate of the mean salary for all college graduates in this town?
b. Determine the sample size used for the analysis. (Round "z" value to 3 decimal places and final answer to the nearest whole number.)
In: Math
You read in the results section of an article in a psychology journal that the results of at-test for independent sample means revealed a significant t12 = 1.8, with σˆX1−X2 = 2. If there were 8 participants in the experimental group,
(a) how many participants were in the corresponding control group?
(b) what significance level was used, and was the test a one-tailed or a two-tailed test?
(c) what was the mean difference between the experimental and the control groups?
In: Math
The length of time for an individual to wait at a lunch counter is a random variable whose density function is
f(x) = (1/4)e^(-x/4) for x > 0 and = 0 otherwise
a) Find the mean and the variance
b) Find the probability that the random variable is within three standard deviations of the mean and compare Chebyshev's Theorem.
In: Math
Problem 8-12 (Algorithmic)
Many forecasting models use parameters that are estimated using nonlinear optimization. The basic exponential smoothing model for forecasting sales is
Ft + 1 = αYt + (1 – α)Ft
where
Ft + 1 | = | forecast of sales for period t + 1 |
Yt | = | actual value of sales for period t |
Ft | = | forecast of sales for period t |
α | = | smoothing constant 0 ≤ α ≤ 1 |
This model is used recursively; the forecast for time period t + 1 is based on the forecast for period t, Ft; the observed value of sales in period t, Yt and the smoothing parameter α. The use of this model to forecast sales for 12 months is illustrated in the table below with the smoothing constant α = 0.3. The forecast errors, Yt - Ft, are calculated in the fourth column. The value of α is often chosen by minimizing the sum of squared forecast errors, commonly referred to as the mean squared error (MSE). The last column of Table shows the square of the forecast error and the sum of squared forecast errors.
EXPONENTAL SMOOTHING MODEL FOR α=0.3 | ||||||||
Week () |
Observed Value () |
Forecast | Forecast Error () |
Squared Forecast Error | ||||
1 | 16 | 16.00 | 0.00 | 0.00 | ||||
2 | 20 | 16.00 | 4.00 | 16.00 | ||||
3 | 18 | 17.20 | 0.80 | 0.64 | ||||
4 | 24 | 17.44 | 6.56 | 43.03 | ||||
5 | 21 | 19.41 | 1.59 | 2.53 | ||||
6 | 16 | 19.89 | -3.89 | 15.13 | ||||
7 | 19 | 18.72 | 0.28 | 0.08 | ||||
8 | 21 | 18.80 | 2.20 | 4.84 | ||||
9 | 24 | 19.46 | 4.54 | 20.61 | ||||
10 | 22 | 20.82 | 1.18 | 1.39 | ||||
11 | 12 | 21.17 | -9.17 | 84.09 | ||||
12 | 19 | 18.42 | 0.58 | 0.34 | ||||
SUM=188.68 |
In using exponential smoothing models, we try to choose the value of α that provides the best forecasts. Build an Excel Solver or LINGO optimization model that will find the smoothing parameter, α, that minimizes the sum of squared forecast errors. You may find it easiest to put table into an Excel spreadsheet and then use Solver to find the optimal value of α. If required, round your answer for α to three decimal places and the answer for the resulting sum of squared errors to two decimal places.
The optimal value of α is and the resulting sum of squared errors is .
In: Math
A university would like to examine the linear relationship between a faculty member's performance rating (measured on a scale of 1-20) and his or her annual salary increase. The table to the right shows these data for eight randomly selected faculty members. Complete parts a and b. Rating Increase 16 2300 18 2400 12 1800 12 1600 16 2000 14 2700 18 1900 17 1800
In: Math
Let x be a random variable that represents the percentage
of successful free throws a professional basketball player makes in
a season. Let y be a random variable that represents the
percentage of successful field goals a professional basketball
player makes in a season. A random sample of n = 6
professional basketball players gave the following information.
x | 67 | 65 | 75 | 86 | 73 | 73 |
y | 42 | 40 | 48 | 51 | 44 | 51 |
(c) Verify that Se ≈ 3.0468, a ≈ 8.188, b ≈ 0.5168, and x ≈ 73.167.
Se | = |
(e) Find a 90% confidence interval for y when x = 83. (Round your answers to one decimal place.)
lower limit | % |
upper limit | % |
(f) Use a 5% level of significance to test the claim that
β > 0. (Round your answers to two decimal places.)
t | |
critical t |
In: Math
Ch. 11, 2. Given two dependent random samples with the following results:
Population 1 |
71 |
68 |
50 |
84 |
76 |
76 |
80 |
79 |
Population 2 |
76 |
63 |
54 |
80 |
79 |
82 |
75 |
82 |
Can it be concluded, from this data, that there is a significant difference between the two population means?
Let d= (Population 1 entry)−(Population 2 entry)d=(Population 1 entry)−(Population 2 entry). Use a significance level of α=0.2 for the test. Assume that both populations are normally distributed.
Step 1 of 5: State the null and alternative hypotheses for the test.
Ho: μd(=,≠,<,>,≤,≥) 0
Ha:μd (=,≠,<,>,≤,≥) 0
Step 2 of 5: Find the value of the standard deviation of the paired differences. Round your answer to one decimal place.
Step 3 of 5: Compute the value of the test statistic. Round your answer to three decimal places.
Step 4 of 5: Determine the decision rule for rejecting the null hypothesis H0. Round the numerical portion of your answer to three decimal places.
Reject Ho if (t, I t I) (<,>) _____
Step 5 of 5:
Make the decision for the hypothesis testTop of Form
Reject Null Hypothesis Fail to Reject Null Hypothesis
In: Math
1) 75% of adult smokers started smoking before turning 18 years in a population. A random sample of 30 smokers 18 years or older are selected and the number of smokers who started smoking
before 18 is recorded.
1) Find the probability that exactly 7 are smokers.
2) Find the probability that at least 5 are smokers.
3) Find the probability that fewer than 3 are smokers.
4) Find the probability that between 4 and 7 of them, inclusive, are smokers.
5) Find the mean and standard deviation of this binomial experiment.
6) The mean value for an event X to occur is 2 in a day. Find the probability of event X to happen 3 times in a day.
8) Find the probability mass function of Poisson distribution.
Define moment generating function for discrete and continuous distribution.
9) Find the mean and variance of Poisson distribution using MGF.
In: Math
A poll printed the results of a survey of 880Americans focusing on their perception of the quality of Japanese products. It has been observed that the sentiment towards Japanese products has actually improved over time. Is there sufficient evidence to conclude that American sentiment towards Japanese products changed from 1999 to 2005?
Opinion | 1999 | 2005 |
---|---|---|
Good to Excellent | 24% | 28% |
Average | 27% | 40% |
Below Average | 18% | 3% |
No Opinion | 31% | 29% |
Step 8 of 10 : Find the critical value of the test at the 0.05 level of significance. Round your answer to three decimal places.
Step 9 of 10: Make the decision to reject or fail to reject the null hypothesis at the 0.05 level of significance.
Step 10 of 10: State the conclusion of the hypothesis test at the 0.05 level of significance.
In: Math
A researcher obtained the ordinary least squares (OLS) estimates for a Ghanaian firm's stock price using 120 observations from 1980 ml to 1989 m 12 (All variables in logarithms) as:
In St = 0.87 -054 In pt + 0.65 In yt + 0.34 In rt - 0.32 In mt
Standard errors:
pt = (1.06)
yt = (0.24)
rt = (0.12)
mt = (0.24)
Adjusted R2=0.34, RSS = 1.24, F1154 =3.75
St are the log of the stock price, pt is the log of profit, yt is the log of its output in Ghana, rt is the log of expenditure on research and development and mt is the log of expenditure on marketing. Figures in parentheses are standard errors and RSS is the Residual Sum of squares.
Required:
(a) Interpret fully the regression results.
(b) Briefly evaluate the reasons behind including pt and yt as explanatory variables in the regression
(c) What is the explanatory power of the regression?
(d) Test, whether each coefficient equals 0, at the 5% level of significance
(e) Using a t-test, does the coefficient on the variable In yt = 1?
(f) What are the policy implication of the result
In: Math
Meteorites randomly strike the earth’s surface at an average rate of 90 meteorites per hour.
(a) Find the probability that at least 4 meteorites strike the earth during a three-minute interval.
(b) Find the probability that the time between two consecutive meteorites striking the earth is greater than 20 seconds. Derive the formulation using the c.d.f., but do not calculate it.
(c) Find the probability that the time until 4 meteorites strike the earth is greater than 2 minutes.
(d) Calculate the expected time until 4 meteorites strike the earth.
I know we use poissons distribution but im having trouble breaking down and understanding this problem.
In: Math
40 numbers are rounded off to the nearest integer and then summed. If the individual round-off error are uniformly distributed over (−.5,.5) what is the probability that the resultant sum differs from the exact sum by more than 2 ?
In: Math