A biologist studying lizards, specifically Cophosaurus texanus, recorded the wei
ID: 3229387 • Letter: A
Question
A biologist studying lizards, specifically Cophosaurus texanus, recorded the weight (mass) in grams, snout-vent length (SVL) and hind limb span (HLS) of a random sample of 25 such lizards. The biologist wants to study the relationship between variables, looking to see if SVL can be used to predict weight (mass) accurately. A basic scatterplot shows the data at right. A student working in the biologist's lab runs a regression analysis on the data and produces the following partial R output: Residual standard error: 0.6986 on 23 degrees of freedom Multiple R-squared: 0.9349, Adjusted R-squared: 0.9321 F-statistic: 330.5 on 1 and 23 DE, p-value: 3.S36e-15 f. Now, we want to assess whether or not SVL can be used to predict mass (weight). What hypotheses correspond to determine if SVL is a significant predictor Null hypothesis: Alternative Hypothesis: Test Statistic: Distribution of Test Stat: p-value: Conclusion: g. obtain a 95% confidence interval for the population slope.(You do not need to list assumptions). Interpret your interval. Can you conclude the population slope is less than 1? Explain.Explanation / Answer
f. Null HYpothesis : H0 : There is no significant effect of SVL to predict mass weight. SVL is not a significant predictor. B1 = 0.
Alternative Hypothesis : Ha : There is significant effect of SVL to predict mass weight. SVL is a significant predictor . B1 0.
TestStatistic t = 18.18
Distribution of test : student t' distribution
p - value = 3.84 * 10-15
COnclusion: Slope coefficent is significant in nature and we can reject the null hypothesis. We can say that SVL is an effective predictor for weight.
g. 95 % confidence ineterval for population slope.
= B1 +- t0.025, 23 SEe = 0.32459 + 2.069* 0.01786 = (0.2876, 0.3615)
We can intrepret that the slope coefficent could be in between 0.28 to 0.36, so the interval is no very large. We can also concude that the population slope is less than 1 because it is 95% sure that it is not under the confidence interval values.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.