Sarah got a 80% on her pre algebra final exam. if there were 75 questions total how many did sarah get correc? How many did she
2 answers:
Answer: Sarah got 60 questions correct, 15 questions wrong, and she got 20% of the questions wrong.
Step-by-step explanation:
First, let's solve for how many questions Sarah got correct.
80% as a fraction can be simplified as . To find how many questions Sarah answered correctly, we can set up a proprtional relationship as follows:
Next, after we cross multiply, 8 X 75 = 600, and 600 ÷ 10 = 60
So, Sarah got 60 out of 75 questions correct.
To find how many she missed, we can simply subtract 60 from 75 to get 15.
So, Sarah got 15 out of 75 questions wrong.
Finally, to find the percentage of the questions that Sarah got wrong, we can use the 15 out of 75 incorrect questions that we found earlier to create a percentage.
15 ÷ 75 = 0.2
0.2 X 100 = 20
So, Sarah got 20% of the questions wrong.
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Answer:
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,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.
Step-by-step explanation:
Data given and notation
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if thetrue mean is below the specifications, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
If we analyze the size for the sample is > 30 and we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:
(1)
z-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".
Calculate the statistic
We can replace in formula (1) the info given like this:
P-value
Since is a one sided 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,and we have enough evidence to conclude that the true mean is significantly lower thn 4.8 at 10% of signficance.