Can someone plz help me with all these problems

A 0.3 kilogram softball is thrown toward a catcher's mitt. the ball is accelerating at a rate of 8 meters per second squared wit

schepotkina [342]

Force = mass * acceleration
Force = 0.3 km * 8m = 2.4 N
I got a different answer from a,b,c

4 0

2 years ago

HELP ME PLEASE PLEASE

olga_2 [115]

i really thinks its 6.9*10 to the power of 2

4 0

1 year ago

there are 250 people in a museum. 2/5 of the 250 people are girls. 3/10 of the 250 people are boys. the rest of the 250 people a

Akimi4 [234]

His is:-

250 - 2/5 *250 - 3/10 * 250

= 250 - 100 - 75

= 250 - 175

= 75 answer

7 0

3 years ago

Read 2 more answers

A random sample from a normal population is obtained, and the data are given below. Find a 90% confidence interval for . 114 157

melamori03 [73]

Answer:

$103.160 \leq \sigma \leq 187.476$

And the upper bound rounded to the nearest integer would be 187.

Step-by-step explanation:

Previous concepts

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 .

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

Data given: 114 157 203 257 284 299 305 344 378 410 421 450 478 480 512 533 545

The confidence interval for the population variance $\sigma^2$ is given by the following formula:

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

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^{17} (x_i -\bar x)^2}{n-1}}$

And in order to find the sample mean we just need to use this formula:

$\bar x =\frac{\sum_{i=1}^n x_i}{n}$

The sample mean obtained on this case is $\bar x= 362.941$ and the deviation s=132.250

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

$df=n-1=17-1=16$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical values.