3. A before and after approach is most appropriate when:
a) there is simultaneous causality.
b) there is measurement error in the explanatory or dependent variable.
c) there is an omitted variable that varies across entities, but not over time.
d) there is an omitted variable that varies over time, but not across entities.
In: Economics
What are the standard precautions and infection control steps that are necessary before and after use of an exam/treatment room?
In: Nursing
Age is sometimes measured in years before and after peak height velocity (PHV). What is the advantage of this and what does this practice allow us to do?
In: Nursing
In the week before and the week after a holiday, there were 10 comma 000 total deaths, and 4917 of them occurred in the week before the holiday. a. Construct a 95% confidence interval estimate of the proportion of deaths in the week before the holiday to the total deaths in the week before and the week after the holiday. b. Based on the result, does there appear to be any indication that people can temporarily postpone their death to survive the holiday?
In: Statistics and Probability
• The following are mood scores for 12 participants before and after watching a funny video clip (higher values indicate better mood). Before After Before After 7 2 4 2 5 4 7 3 5 3 4 1 7 5 4 1 6 5 5 3 7 4 4 3 a. Calculate the paired-samples t statistic for these mood scores. b. Using a one-tailed hypothesis test that the video clip improves mood, and a p level of 0.05, identify the critical tvalues and make a decision regarding the null hypothesis. c. Using a two-tailed hypothesis test with a p level of 0.05, identify the critical t values and make a decision regarding the null hypothesis. I need to show all steps. Also can you send me the answer only and not post it on the web. I am paying Chegg to get help and the answer to my question is posted and then everyone turns in my exact answer regarding the manner it is answered and I get in trouble.
In: Statistics and Probability
in a study of thermal annealing process, hardness of steel is measured before annealing and after annealing. a group of 16 samples measured and the test results are given in the table below
before ann 209 178 169 212 180 192 158 180 170 153 183 165 201 179 243 144
after ann 196 171 170 207 177 190 159 180 164 152 179 162 199 173 231 140
In: Statistics and Probability
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A restaurant wants to test the quality of service before training and after training. Their objective is to determine if the training is effective in improving their service standards. The staff were evaluated on a scale of 1 to 10 with1 being very bad and 10 being very good. Using an appropriate test determine if the training was effective in achieving its objective. The following table displays the results of the study:
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i) |
If di represents the difference in index (after training – before training) for participant i, find di for i = 1,….,6. Using your calculator or otherwise determine the mean, and standard deviation of di.to four decimal places |
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In: Statistics and Probability
| ID | After | Before |
| 1 | 1230 | 1074 |
| 2 | 1090 | 1039 |
| 3 | 1028 | 1004 |
| 4 | 1230 | 1154 |
| 5 | 1200 | 1144 |
| 6 | 1030 | 974 |
| 7 | 1220 | 1174 |
| 8 | 1085 | 1134 |
| 9 | 1000 | 1094 |
| 10 | 1320 | 1174 |
| 11 | 1075 | 1004 |
| 12 | 1040 | 1014 |
| 13 | 1030 | 1114 |
| 14 | 1110 | 1134 |
| 15 | 995 | 1079 |
| 16 | 1160 | 1184 |
| 17 | 1250 | 1254 |
| 18 | 1000 | 994 |
| 19 | 1110 | 1024 |
| 20 | 1045 | 1004 |
| 21 | 925 | 884 |
| 22 | 1005 | 1044 |
| 23 | 1150 | 1054 |
| 24 | 1015 | 1019 |
| 25 | 980 | 934 |
| Q4. Calculate the mean difference in scores (After - Before) and the sample variance of the difference. |
| Mean Difference ==> |
| Sample Variance of Difference ==> |
| Q5. Calculate the LCL and UCL for a 90% CI (α = 0.1) for the mean difference in scores. |
| LCL ==> |
| UCL ==> |
| Based on this 90% interval, would you say the prep course improved scores (Yes/No) |
| Q6. Calculate the LCL and UCL for a 95% CI (α = 0.05) for the mean difference in scores. |
| LCL ==> |
| UCL ==> |
| Based on this 95% interval, would you say the prep course improved scores (Yes/No) |
In: Statistics and Probability
and the week before and the week after a holiday there were eleven thousand total deaths and 5489 of them occurred in the week before the holiday construct a 90% confidence interval estimate of the proportion of deaths in the week before the holiday to the total deaths in the week before and the week after the holiday based on the result does there appear to be any indication that people can temporarily postponed their death to survive the holiday
In: Statistics and Probability
psychological test before and after treatment in order to determine the effectiveness of the treatment. Researchers hope to find a difference in test scores before and after treatment. A 95% CI for the population average difference in test scores (before-after) is given by (0.25, 3.75), which was computed based on a random sample of 36 patients.
a) What is the population parameter of interest? mu1? mu2? mud?
b) Based on the confidence interval, at a 5% significance level, would 0 be considered a reasonable value of the population parameter?
c) Based on the CI, what is the value of the sample statistic (point estimate)?
d) Based on the CI and the sample statistics found in c). What is the value of the standard error (SE) of the sample statistic? Hint: UB = point estimate + margin of error = Xd+E= Xd+cv X SE(Xd)
e) Is there a significant difference in test scores (before - after) on average? Perform an appropriate hypothesis test using α = 0.10.
I. List data assumptions.
II. State H0 and Ha.
III. Calculate the test statistic.
IV. Make decision using the rejection region approach.
V. Draw conclusion.
In: Statistics and Probability