HELP ME PLZ

How much force is needed to accelerate a 66kg skier 1m/sec/sec?

Sphinxa [80]

Answer: The answer is Thus, a force of 132 N is needed to accelerate a skier, having a mass of 66 kg, by 2 m/s^2.

Step-by-step explanation:

4 0

3 years ago

The ages of a random sample of five university professors are 39, 54, 61, 72, and 59. Using this information, find a 99% confide

blsea [12.9K]

Answer:

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

Step-by-step explanation:

Data given and notation

34,59,61,71,59

We can calculate the sample standard deviation with the following formula:

$s^2= \frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$s= \sqrt{s^2}$

s=12.021 represent the sample standard deviation

$\bar x$ represent the sample mean

n=5 the sample size

Confidence=99% or 0.99

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=5-1=4$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.005,4)" "=CHISQ.INV(1-0.005,4)". so for this case the critical values are:

$\chi^2_{\alpha/2}=14.860$

$\chi^2_{1- \alpha/2}=0.207$

And replacing into the formula for the interval we got:

$\frac{(4)(12.021)^2}{14.860} \leq \sigma^2 \leq \frac{(4)(12.021)^2}{0.207}$

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

3 0

3 years ago

Read 2 more answers

A freight train is carrying goods across the country. The number of gallons of fuel it has used varies directly with the distanc

Maru [420]

Answer:

0.125 miles per gallon.

Step-by-step explanation:

After 200 gallons used the freight train has traveled 25 miles. This means that we need to divide both sides by 200 to get a singular gallon's worth of miles traveled. 200/200 is 1, and 25/200 is 0.125.

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Extra

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IF it were how many gallons per mile, you would divide both answers by 25 resulting in 8 gallons per mile.

6 0

4 years ago

Read 2 more answers

What is the volume of a hemisphere with a radius of 34.1 in, rounded to the nearest tenth of a cubic inch?

White raven [17]

Answer:83046.6

Step-by-step explanation:

4 0

3 years ago

Heeeeeelllllllppppppp

EleoNora [17]

Answer:

Step-by-step explanation:

-7k = 0

Divide both sides by (-7)

k = 0

17) c - 4 = -23

Add 4 to both sides

c - 4 + 4 = -23 + 4

c = - 19

$18) \dfrac{r}{-2}=-16\\\\\\Multiply \ both \ sides \ by \ (-2)\\\\\dfrac{r}{-2}*(-2) = (-16)*(-2)\\\\\\r = 32$

8 0

3 years ago