One kilometre is about 0.62 miles. It is 12 kilometres from Noah's house to the

Mathematics

1 answer:

Setler [38]3 years ago

8 0

Answer:

7.44miles

Step-by-step explanation:

1km = 0.62miles

12km will be ; 0.62 × 12

= 7.44miles

You might be interested in

An item originally costs $16.95 and is on sale for 22% off the original price. The sales tax is 6.5%. Find the cost of the item

olga_2 [115]

Answer:

$14.08

Step-by-step explanation:

$16.95 * 22% = $3.729

$16.95 - $3.729 = $13.221

^ to find the sale price of the item

$13.221 * 6.5% = $0.859

$13.221 + $0.859 = $14.08

^ to add on sales tax to the sale price

8 0

3 years ago

There are 2,000 eligible voters in a precinct. A total of 500 voters are randomly selected and asked whether they plan to vote f

Ann [662]

Answer:

$0.7 - 2.58 \sqrt{\frac{0.7(1-0.7)}{500}}=0.647$

$0.7 + 2.58 \sqrt{\frac{0.7(1-0.7)}{500}}=0.753$

And the 99% confidence interval would be given (0.647;0.753).

So the correct answer would be:

a. 0.647 and 0.753

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 means 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.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Solution to the problem

The estimated population proportion for this case is:

$\hat p = \frac{350}{500}=0.7$

The confidence interval would be given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 99% confidence interval the value of $\alpha=1-0.99=0.01$ and $\alpha/2=0.005$ , with that value we can find the quantile required for the interval in the normal standard distribution.