Can someone verify her answer please
1 answer:
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Answer:
The half-life of the radioactive substance is of 3.25 days.
Step-by-step explanation:
The amount of radioactive substance is proportional to the number of counts per minute:
This means that the amount is given by the following differential equation:
In which k is the decay rate.
The solution is:
In which Q(0) is the initial amount:
8000 counts per minute on a Geiger counter at a certain time
This means that
500 counts per minute 13 days later.
This means that . We use this to find k.
So
Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So
The half-life of the radioactive substance is of 3.25 days.
Answer:
a) We need to conduct a hypothesis in order to check if the true mean is more than 3900 bus miles, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
If we compare the p value and the significance level given we see that
so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 3900 bis miles at 10% of signficance.
b)
Step-by-step explanation:
Data given and notation
represent the sample mean
represent the sample standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
t would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
Assuming this question for part a: Is there evidence that the population mean bus miles is more than 3,700 bus miles? (Use a 0.10 level ofsignificance.) Because is if 3700 not makes sense based on the previous info
Part a: State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the true mean is more than 3900 bus miles, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
(1)
t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
Part b: Calculate the statistic
We can replace in formula (1) the info given like this:
P-value
The first step is calculate the degrees of freedom, on this case:
Since is a one side test the p value would be:
Conclusion
If we compare the p value and the significance level given we see that
so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 3900 bis miles at 10% of signficance.