A biologist looked at the relationship between number of seeds a plant produces and the percent of those seeds that sprout. The results of the survey are shown below. Seeds Produced 58 61 58 68 51 54 67 Sprout Percent 60 65.5 67 50 73.5 71 53.5 Find the correlation coefficient: r=r= Round to 2 decimal places. The null and alternative hypotheses for correlation are: H0:H0: == 0 H1:H1: ≠≠ 0 The p-value is: (Round to four decimal places) Use a level of significance of α=0.05α=0.05 to state the conclusion of the hypothesis test in the context of the study. There is statistically insignificant evidence to conclude that there is a correlation between the number of seeds that a plant produces and the percent of the seeds that sprout. Thus, the use of the regression line is not appropriate. There is statistically significant evidence to conclude that a plant that produces more seeds will have seeds with a lower sprout rate than a plant that produces fewer seeds. There is statistically significant evidence to conclude that there is a correlation between the number of seeds that a plant produces and the percent of the seeds that sprout. Thus, the regression line is useful. There is statistically insignificant evidence to conclude that a plant that produces more seeds will have seeds with a lower sprout rate than a plant that produces fewer seeds.
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
A biologist looked at the relationship between number of seeds a plant produces and the percent of those seeds that sprout. The results of the survey are shown below.
Seeds Produced | 58 | 61 | 58 | 68 | 51 | 54 | 67 |
---|---|---|---|---|---|---|---|
Sprout Percent | 60 | 65.5 | 67 | 50 | 73.5 | 71 | 53.5 |
- Find the
correlation coefficient : r=r= Round to 2 decimal places. - The null and alternative hypotheses for correlation are:
H0:H0: == 0
H1:H1: ≠≠ 0
The p-value is: (Round to four decimal places) - Use a level of significance of α=0.05α=0.05 to state the conclusion of the hypothesis test in the context of the study.
- There is statistically insignificant evidence to conclude that there is a correlation between the number of seeds that a plant produces and the percent of the seeds that sprout. Thus, the use of the regression line is not appropriate.
- There is statistically significant evidence to conclude that a plant that produces more seeds will have seeds with a lower sprout rate than a plant that produces fewer seeds.
- There is statistically significant evidence to conclude that there is a correlation between the number of seeds that a plant produces and the percent of the seeds that sprout. Thus, the regression line is useful.
- There is statistically insignificant evidence to conclude that a plant that produces more seeds will have seeds with a lower sprout rate than a plant that produces fewer seeds.
- r2r2 = (Round to two decimal places)
- Interpret r2r2 :
- There is a 89% chance that the regression line will be a good predictor for the percent of seeds that sprout based on the number of seeds produced.
- There is a large variation in the percent of seeds that sprout, but if you only look at plants that produce a fixed number of seeds, this variation on average is reduced by 89%.
- Given any group of plants that all produce the same number of seeds, 89% of all of these plants will produce seeds with the same chance of sprouting.
- 89% of all plants produce seeds whose chance of sprouting is the average chance of sprouting.
- The equation of the linear regression line is:
ˆyy^ = + xx (Please show your answers to two decimal places) - Use the model to predict the percent of seeds that sprout if the plant produces 57 seeds.
Percent sprouting = (Please round your answer to the nearest whole number.) - Interpret the slope of the regression line in the context of the question:
- As x goes up, y goes down.
- For every additional seed that a plant produces, the chance for each of the seeds to sprout tends to decrease by 1.32 percent.
- The slope has no practical meaning since it makes no sense to look at the percent of the seeds that sprout since you cannot have a negative number.
- Interpret the y-intercept in the context of the question:
- The average sprouting percent is predicted to be 141.3.
- The best prediction for a plant that has 0 seeds is 141.3 percent.
- If plant produces no seeds, then that plant's sprout rate will be 141.3.
- The y-intercept has no practical meaning for this study.
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