Choose the right test to use for the following situations.You need to test for d
ID: 3355769 • Letter: C
Question
Choose the right test to use for the following situations.You need to test for differences between two samples in the 3 different situations below.
Provide the name of the test and explain why you chose it! Parametric/Nonparametric, Independent/Paired
If you chose the Independent Samples t-test mention which variant and why.
Also explain why it should be a one- or a two-tailed test?
Choose from: Independent/pared t-test, Mann Whitney U or Wilcoxon signed-rank test.
a- The two samples each contain 40 randomly selected plants. One control and one treatment group. Everything was kept constant (light, water, soil, etc...) except the treatment which was fertilizer. You measured the height of the plants in millimeters and analyzed the data with the Shapiro Wilk test, the outcome was p = 0.42. You also ran Levene’s test and the outcome was 0.062.
b- The following situation has ordinal data with a normal distribution. A treatment was given and it was expected to have a positive effect, it definitely could not have a negative effect on the outcome. Of the two samples, each contain the same 50 individuals that were measured twice, once at the start of the experiment and once again after the treatment.
C-The two samples are one control group and one treatment group, each containing 85 randomly selected individuals. The individuals were tested on their knowledge of science, they received a score between A-F. The data was graphed in a histogram and came out approximately symmetrical. The treatment group participated in an evening science class, while the control group did not.
Please double check whether you explained why you chose a certain test and whether you used a one or two tailed test.
Explanation / Answer
Result:
Choose the right test to use for the following situations.You need to test for differences between two samples in the 3 different situations below.
Provide the name of the test and explain why you chose it! Parametric/Nonparametric, Independent/Paired
If you chose the Independent Samples t-test mention which variant and why.
Also explain why it should be a one- or a two-tailed test?
Choose from: Independent/pared t-test, Mann Whitney U or Wilcoxon signed-rank test.
a- The two samples each contain 40 randomly selected plants. One control and one treatment group. Everything was kept constant (light, water, soil, etc...) except the treatment which was fertilizer. You measured the height of the plants in millimeters and analyzed the data with the Shapiro Wilk test, the outcome was p = 0.42. You also ran Levene’s test and the outcome was 0.062.
since both Levene’s test and Shapiro Wilk test are not significant, data are normal and with equal variance. Parametric, Independent sample t-test with equal variance is used. This is a two-tailed test because we are not expecting any group is large or small.
b- The following situation has ordinal data with a normal distribution. A treatment was given and it was expected to have a positive effect, it definitely could not have a negative effect on the outcome. Of the two samples, each contain the same 50 individuals that were measured twice, once at the start of the experiment and once again after the treatment.
There are two groups and the data were measured twice. This is pre post data. Data follows normal distribution.
Option 1. We may get the difference of scores between the two occasions for the two groups. We may use independent sample t test for the difference of scores. This is a two tailed test.
Option2: we may use Analysis of covariance for comparing two groups of post data with before data as covariate.
C-The two samples are one control group and one treatment group, each containing 85 randomly selected individuals. The individuals were tested on their knowledge of science, they received a score between A-F. The data was graphed in a histogram and came out approximately symmetrical. The treatment group participated in an evening science class, while the control group did not.
Data are ordinal because score between A-F. Nonparametric test used.
Independent sample test is used because two independent groups are studied.
Independent sample Mann Whitney U test is used. This is a two tailed test because any group is better than the other.