a jogger ran 3 miles due east of his house. then he ran 5 miles at a heading of 30 east of north. how far is he from his house a
1 answer:
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Answer:
4/5 hour . . . . 48 minutes
Step-by-step explanation:
In hours, the total time is ...
... 1/10 + 1/5 + 1/2 = 1/10 + 2/10 + 5/10
... = (1+2+5)/10 = 8/10
... = 4/5
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You can have a calculator add these numbers for you. Most will report the result as a decimal. There are fraction calculators on-line, if your graphing calculator does not have a fraction display mode.
If you want minutes, multiply the fraction (or decimal) by 60 minutes.
Answer:
The hippocampus volumes in the alcoholic adolescents are less than the normal volume of 9.02 cm³
Step-by-step explanation:
Let x= the hippocampus volumes in the alcoholic adolescents
We'll conduct a hypothesis test at the 0.01 significance level with
Null hypothesis: x = 9.02 cm³
Alternate hypothesis: x < 9.02 cm³
A sample of 13 alcoholic adolescents gives the parameters
size=N= 13
mean=M= 8.12 cm³
standard deviation= s= 0.8 cm³
According to the sample, with 99% confidence, t statistic for the value X=9.02 can be found using the formula:
t= where
- M is the sample mean (8.12)
- s is the standard deviation of the sample (0.8)
- N is the sample size (13)
If we put these numbers in the formula:
t= =4.056
One tailed critical value for the sample with 12 degrees of freedom (sample size-1) in 99% confidence level is 2.681.
Since t value (4.056) is bigger than the critical value, we fail to reject the alternate hypothesis, therefore reject the null hypothesis and accept alternate hypothesis.