If a car has tires with a radius of 1.5 ft and the tires are spinning at 840 rpm (revolutions per
1 answer:
Answer:
89·98 mph
Step-by-step explanation:
First, we get the circumference of the tires:
Circumference = × (radius × 2)
Circumference = 3.142 × (1·5 × 2)
Circumference = 3·142 × 3
Circumference = 9·426 ft
The circumference of the tire is equal to one round.
1 round = 9·426 ft
840 rounds = ?
We cross multiply to get the length that the tires would cover in a minute
= <u>840 × 9·426</u>
1
1 minute = 7917·84 ft
60 minutes = ?
<u>60 × 7917·84</u>
1
= 475070·4 ft
5280 feet = 1 mile
475070·4 feet = ?
<u>475070·4 × 1</u>
5280
475070·4 ÷ 5280 = speed of the car in mph
89·97545
Round this off to 2 decimal places...
= 89·98 mph
hope this helps! =)
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The decision rule for rejecting the null hypothesis, considering the t-distribution, is of:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
At the null hypothesis, it is tested if there is not enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means is of zero, hence:
At the alternative hypothesis, it is tested if there is enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means different of zero, hence:
We have a two-tailed test, as we are testing if the mean is different of a value.
Considering the significance level of 0.05, with 75 + 46 - 2 = 119 df, the critical value for the test is given as follows:
|t| = 1.9801.
Hence the decision rule is:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
More can be learned about the t-distribution in the test of an hypothesis at brainly.com/question/13873630
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