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3 years ago

- On Tuesday, Elena completed 20 items of her math homework in 36 minutes. At that same rate, how long (

Mathematics

1 answer:

Tema [17]3 years ago

4 0

Answer:

Step-by-step explanation

20=36

1=x

Then cross multiply

20x=36

x=1.8

If it takes her 1.8 minutes to complete 1 item then:

1=1.8

35=x

x=63

It takes her 63 minutes

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3 years ago

A researcher wants to check the claim that convicted burglars spend less than 18.7 months in jail, on average. She takes a rando

vivado [14]

Answer:

a. No, there is not enough evidence to support the claim using a level of significance of 1%.

b. Null Hypothesis, $H_0$ : $\mu \geq$ 18.7 months

c. Alternate Hypothesis, $H_A$ : $\mu$ < 18.7 months

d. P-value of hypothesis test = 0.0199 or 1.99%

e. We conclude that the convicted burglars spend more than or equal to 18.7 months in jail, on average.

Step-by-step explanation:

We are given that a researcher wants to check the claim that convicted burglars spend less than 18.7 months in jail, on average.

She takes a random sample of 67 such cases from court files and finds that the mean is 16.8 months with a standard deviation of 7.3 months.

Let $\mu$ = true mean time convicted burglars spend in jail.

SO, Null Hypothesis, $H_0$ : $\mu \geq$ 18.7 months {means that the convicted burglars spend more than or equal to 18.7 months in jail, on average}

Alternate Hypothesis, $H_A$ : $\mu$ < 18.7 months {means that the convicted burglars spend less than 18.7 months in jail, on average}

The test statistics that will be used here is One-sample t test statistics as we don't know about the population standard deviation;

T.S. = $\frac{\bar X -\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean time spent in jail = 16.8 months

s = sample standard deviation = 7.3 months

n = sample of cases = 67

So, test statistics = $\frac{16.8-18.7}{\frac{7.3}{\sqrt{67} } }$ ~ $t_6_6$

= -2.13

Hence, the value of test statistics is -2.13.

Now, P-value of the test statistics is given by;

P-value = P( $t_6_6$ < -2.13) = 0.0199 or 1.99%

If the P-value of test statistics is more than the level of significance, then we will not reject our null hypothesis as it will not fall in the rejection region.

If the P-value of test statistics is less than the level of significance, then we will reject our null hypothesis as it will fall in the rejection region.

Now, here the P-value is 0.0199 or 1.99% which is clearly higher than the level of significance of 1%, so we will not reject our null hypothesis as it will not fall in the rejection region.

Therefore, we conclude that the convicted burglars spend more than or equal to 18.7 months in jail, on average.

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3 years ago

Joan and her brother Justin left a hotel at the same time, driving in opposite directions at constant rates. After traveling for

inessss [21]

Answer:

Joan drive with a speed of 55 miles per hour.

Step-by-step explanation:

Given:- Travelling time (t) = 4 hours.

Travelled distance (d) = 480 miles.

Speed of Justin is 10 miles per hour faster than Joan.

To find:- Speed of Joan = ?