According to a study on reptiles from decades ago, the mean lifespan of giant Aldabra tortoises in the wild is 98.3 years. Many of the areas where these tortoises live have become polluted with plastic waste. Because of this, a biologist claims the mean lifespan of these tortoises has decreased. To test this claim, the biologist conducted a study of 21 randomly selected, giant Aldabra tortoises in the wild. In the study, the sample mean lifespan was 96.3 years with a sample standard deviation of 15.2 years. Assume that the population of lifespans of giant Aldabra tortoises in the wild is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.10 level of significance, to support the claim that μ , the mean lifespan of giant Aldabra tortoises in the wild, is now less than 98.3 years. (a) State the null hypothesis H0 and the alternative hypothesis H1 that you would use for the test. H0 : H1 : (b)Perform a t test and find the p-value. Here is some information to help you with your t test. The value of the test statistic is given by =t−xμsn . The p-value is the area under the curve to the left of the value of the test statistic. Student's t Distribution Step 1: Enter the number of degrees of freedom. Step 2: Select one-tailed or two-tailed. One-tailed Two-tailed Step 3: Enter the test statistic. (Round to 3 decimal places.) Step 4: Shade the area represented by the p-value. Step 5: Enter the p-value. (Round to 3 decimal places.) 0.1 0.2 0.3 0.4 1 −1 2 −2 3 −3 (c)Based on your answer to part (b), choose what can be concluded, at the 0.10 level of significance, about the claim made by the biologist. Since the p-value is less than (or equal to) the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than 98.3 years. Since the p-value is less than (or equal to) the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than 98.3 years. Since the p-value is greater than the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than 98.3 years. Since the p-value is greater than the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than 98.3 years.
According to a study on reptiles from decades ago, the
years. Many of the areas where these tortoises live have become polluted with plastic waste. Because of this, a biologist claims the mean lifespan of these tortoises has decreased. To test this claim, the biologist conducted a study of
randomly selected, giant Aldabra tortoises in the wild. In the study, the sample mean lifespan was
years with a sample standard deviation of
years. Assume that the population of lifespans of giant Aldabra tortoises in the wild is approximately
Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the
level of significance, to support the claim that
, the mean lifespan of giant Aldabra tortoises in the wild, is now less than
years.
(a) State the null hypothesis
and the alternative hypothesis
that you would use for the test.
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Here is some information to help you with your
- The value of the test statistic is given by
=t−xμsn
- The p-value is the area under the curve to the left of the value of the test statistic.
Student's t Distribution
Step 1: Enter the number of degrees of freedom.
Step 2: Select one-tailed or two-tailed.
Step 3: Enter the test statistic.
(Round to 3 decimal places.) Step 4: Shade the area represented by the p-value.
Step 5: Enter the p-value.
(Round to 3 decimal places.) 0.1
0.2
0.3
0.4
1
−1
2
−2
3
−3
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Since the p-value is less than (or equal to) the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than
98.3
Since the p-value is less than (or equal to) the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than
98.3
Since the p-value is greater than the level of significance, the null hypothesis is rejected. So, there is enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than
98.3
Since the p-value is greater than the level of significance, the null hypothesis is not rejected. So, there is not enough evidence to support the claim that the mean lifespan of giant Aldabra tortoises in the wild is now less than
98.3
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