Tardigrades, or water bears, are a type of micro-animal famous for their resilience. In examining the effects of radiation on organisms, an expert claimed that the amount of gamma radiation needed to sterilize a colony of tardigrades no longer has a mean of 1350 Gy (grays). (For comparison, humans cannot withstand more than 10 Gy .) A study was conducted on a sample of 18 randomly selected tardigrade colonies, finding that the amount of gamma radiation needed to sterilize a colony had a sample mean of 1375 Gy , with a sample standard deviation of 75 Gy . Assume that the population of amounts of gamma radiation needed to sterilize a colony of tardigrades is approximately normally distributed.   Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.05 level of significance, to support the claim that μ , the mean amount of gamma radiation needed to sterilize a colony of tardigrades, is not equal to 1350 Gy .

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Tardigrades, or water bears, are a type of micro-animal famous for their resilience. In examining the effects of radiation on organisms, an expert claimed that the amount of gamma radiation needed to sterilize a colony of tardigrades no longer has a mean of

1350
Gy
(grays). (For comparison, humans cannot withstand more than
10
Gy
.) A study was conducted on a sample of
18
randomly selected tardigrade colonies, finding that the amount of gamma radiation needed to sterilize a colony had a sample mean of
1375
Gy
, with a sample standard deviation of
75
Gy
. Assume that the population of amounts of gamma radiation needed to sterilize a colony of tardigrades is approximately normally distributed.

 

Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the

0.05
level of significance, to support the claim that
μ
, the mean amount of gamma radiation needed to sterilize a colony of tardigrades, is not equal to
1350
Gy
.

 

 

(a) State the null hypothesis H, and the alternative hypothesis H, that you would use for the test.
Español
Ho: 0
H1: 0
OSO
O=0
(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=
• The p-value is two times the area under the curve to the right of the value of the test statistic.
Student's t Distribution
0.4
Step 1: Enter the number
of degrees of freedom.
0.3
Step 2: Select one-tailed
or two-tailed.
O One-tailed
O Two-tailed
0.2
Step 3: Enter the test
statistic.
(Round to 3 decimal
places.)
0.H
Step 4: Shade the area
represented by the p-
value.
(c) Based on your answer to part (b), choose what can be concluded, at the 0.05 level of significance, about the claim
made by the expert.
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 amount of
gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy.
?
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 amount
of gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy.
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 amount of gamma
radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy.
Since the p-value is greater than the level of significance, the null hypothesis is not
rejected. Šo, there is not enough evidence to support the claim that the mean amount of
gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy.
Transcribed Image Text:(a) State the null hypothesis H, and the alternative hypothesis H, that you would use for the test. Español Ho: 0 H1: 0 OSO O=0 (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= • The p-value is two times the area under the curve to the right of the value of the test statistic. Student's t Distribution 0.4 Step 1: Enter the number of degrees of freedom. 0.3 Step 2: Select one-tailed or two-tailed. O One-tailed O Two-tailed 0.2 Step 3: Enter the test statistic. (Round to 3 decimal places.) 0.H Step 4: Shade the area represented by the p- value. (c) Based on your answer to part (b), choose what can be concluded, at the 0.05 level of significance, about the claim made by the expert. 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 amount of gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy. ? 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 amount of gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy. 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 amount of gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy. Since the p-value is greater than the level of significance, the null hypothesis is not rejected. Šo, there is not enough evidence to support the claim that the mean amount of gamma radiation needed to sterilize a colony of tardigrades is not equal to 1350 Gy.
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