Step-by-step explanation:
remember. the radius is always half the diameter.
volume of a cylinder
pi × r² × height
pi×7.5²×48 = pi×56.25×48 = 8,482.300165... in³
volume of a sphere
4/3 × pi × r³
and that volume should be the same as the cylinder. so,
4/3 × pi × r³ = pi×56.25×48
4/3 × r³ = 56.25 × 48
1/3 × r³ = 56.25 × 12
r³ = 56.25 × 36 = 7.5² × 6² = (7.5×6)² = 45² = 2025
which would be 12.65148998... in.
Answer:
c. Smoking is associated with lower birth weights. When smokers are compared to nonsmokers, we are 95% confident that the mean weight of babies born to nonsmokers will be between 76.5 grams to 486.9 grams more than the mean birth weight of babies born to smokers.
Step-by-step explanation:
The difference in mean birth weights (nonsmokers minus smokers) is 281.7 grams with a margin of error of 205.2 grams with 95% confidence.
Then, we know that the 95% confidence interval is (76.5, 486.9)
<em>a. We are 95% confident that smoking causes lower birth weights by an average of between 76.5 grams to 486.9 grams.</em>
False, it interprets the confidence interval as a probability for individual cases. The confidence interval is a range for the population mean.
<em>b. There is a 95% chance that if a woman smokes during pregnancy her baby will weigh between 76.5 grams to 486.9 grams less than if she did not smoke.</em>
False, it interprets the confidence interval as a probability for individual cases. The confidence interval is a range for the population mean.
<em>c. Smoking is associated with lower birth weights. When smokers are compared to nonsmokers, we are 95% confident that the mean weight of babies born to nonsmokers will be between 76.5 grams to 486.9 grams more than the mean birth weight of babies born to smokers.</em>
True.
<em>d. With such a large margin of error, this study does not suggest that there is a difference in mean birth weights when we compare smokers to nonsmokers.</em>
There is enough evidence, as the lower bound of the confidence is positive. This means that there is only a probability of 0.05/2=0.025 that the true mean weight difference is smaller than 76.5 grams.