Ok I need help is this correct? I tried but I gave up.

Jason traveled 26 miles. The first 2 hours his speed was 4 mph, and the rest of the way his speed was 3mph. How long was he trav

horsena [70]

Answer: 8 hours

Step-by-step explanation: You would first multiply 2 hours by 4 mph, and get 8 miles. You would then subtract 8 miles from 26 miles, and have 18 miles left. You would now divide 18 miles by 3, as he is now traveling 3 miles per hour and needs to travel 18 miles. You would get 6 hours. You would now add 6 hours by the 2 hours initially traveled at 4 mph, and get 8 hours.

6 0

3 years ago

No question........................

frutty [35]

Answer:

Step-by-step explanation:

ok

8 0

3 years ago

Read 2 more answers

The water works commission needs to know the mean household usage of water by the residents of a small town in gallons per day.

valina [46]

Answer:

A sample of 179 is needed.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.85}{2} = 0.075$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.075 = 0.925$ , so Z = 1.44.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

A previous study found that for an average family the variance is 1.69 gallon?

This means that $\sigma = \sqrt{1.69} = 1.3$

If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?

A sample of n is needed, and n is found for M = 0.14. So

$M = z\frac{\sigma}{\sqrt{n}}$

$0.14 = 1.44\frac{1.3}{\sqrt{n}}$

$0.14\sqrt{n} = 1.44*1.3$

$\sqrt{n} = \frac{1.44*1.3}{0.14}$

$(\sqrt{n})^2 = (\frac{1.44*1.3}{0.14})^2$

$n = 178.8$

Rounding up

A sample of 179 is needed.

7 0

3 years ago

Type the correct answer in each box. Use numerals instead of words. Based on the Pythagorean theorem, find the missing length fo

Neporo4naja [7]

Answer: See below

Step-by-step explanation:

The Pythagorean Theorem is a²+b²=c². Since each problem gives us the length of a, b, or c, we can directly plug them into this equation and solve.

Triangle EFG

9²+b²=41²

81+b²=1681

b²=1600

b=√1600

b=40

----------------------------------------------------------------------

Triangle PQR

20²+21²=c²

400+441=c²

c²=841

c=√841

c=29

----------------------------------------------------------------------

Triangle XYZ

a²+24²=25²

a²+576=625

a²=49

a=√49

a=7

6 0

3 years ago

A population has a mean of 200 and a standard deviation of 50. Suppose a sample of size 100 is selected and x is used to estimat

zmey [24]

Answer:

a) 0.6426 = 64.26% probability that the sample mean will be within +/- 5 of the population mean.

b) 0.9544 = 95.44% probability that the sample mean will be within +/- 10 of the population mean.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .