Draw a pair of opposite rays

You build and sell toy cars for $36 each. So far, you have built 25 toy cars. How many more toy cars will you have to build and

vovikov84 [41]

You need to build 20 more toy cars

8 0

3 years ago

Read 2 more answers

Find each percent change. Round to the nearest tenth of a percent. State if it is an increase or decrease. From 79 miles to 84 m

PolarNik [594]

Answer:

the answer is d.

Step-by-step explanation:

first, you want to use the formula,

new value - original value

____________________

original value * 100

you see that 84 is the new value and 79 would be the original value. substitute the numbers in. this is a increase since you will get a positive value.

84 - 79

______

79 * 100

now we solve it.

5

__

79 * 100

you can either solve the fraction first then multiply that by 100 or multiply the numerator by 100 first then divide that by 79, each way works.

500

____

79 = approximately 6.3% increase (this is not a exact value, just rounded)

or

5

__

79 = approximately 0.063 (this is not a exact value, just rounded)

0.063 * 100 = 6.3% increase

7 0

3 years ago

in a random sample of 200 people, 154 said that they watched educational television. fine the 90% confidence interval of the tru

melisa1 [442]

Answer:

[0.7210,0.8189] = [72.10%, 81.89%]

Step-by-step explanation:

The sample size is

n = 200

the proportion is

p = 154/200 = 0.77

Since both np ≥ 10 and n(1-p) ≥ 10

We can approximate this discrete binomial distribution with the continuous Normal distribution. As the sample size is large enough, not applying the continuity correction factor makes no significant difference.

The approximation would be to a Normal curve with this parameters:

Mean

p = 0.77

Standard deviation

$\bf s=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.77*0.23}{200}}=0.0298$

The 90% confidence interval for the proportion would be then

$\bf [0.77-z^*0.0298, 0.77+z^*0.0298]$

where $\bf z^*$ is the 10% critical value for the Normal N(0,1) distribution , this is a value such that the area under the N(0,1) curve outside the interval $\bf [-z^*,z^*]$ is 10%=0.1