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3 years ago

Here are the heights (in inches) of 12 students in a seminar.

Mathematics

1 answer:

Gala2k [10]3 years ago

5 0

Answer: 75%

Step-by-step explanation:

Height given :

69, 62, 73, 67, 63, 65, 73, 71, 70, 66, 59, 75

The total number of height given = 12

The height less than 73 are 69 , 62, 67 ,63 , 65 , 71 , 70 , 66 , 59

The total number of heights less than 73 = 9

Therefore : the percentage of these students who are shorter than 73 inches = total number of students shorter than 73/ total number of height x 100

= 9/12 x 100

= 75%

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Find the number of palindromes between 10,000 and 99,999 that are divisible by 25

Cerrena [4.2K]

<u><em>20</em> palindromes exist that qualify this criteria rigorously</u>

Examples:

52025, 52125, 52225, 52325, 52425, 52525, 52625, 52725, 52825, 57975 etc.

3 0

2 years ago

Lucy’s parents built a swimming pool in the backyard. Use 3.14 for π.

Rus_ich [418]

Answer:

Distance around the pool = 162.8 feet

Area of the pool = 957 square feet

Step-by-step explanation:

Distance around the swimming pool = Perimeter of the pool

Perimeter of the pool which is a composite figure will be,

= Circumference of the semicircle + Sum of three sides of the pool

= πr + 2×(length of the pool) + width of the pool

= 3.14×(10) + 2×40 + 20

= 62.8 + 80 + 20

= 162.8 ft

Area of the pool = Area of the semicircle + Area of the rectangular pool

= $\frac{1}{2}(\pi)(r)^{2}+(\text{length}\times \text{Width})$

= $\frac{1}{2}(3.14)(10)^2+(40\times 20)$

= 157 + 800

= 957 square feet

8 0

3 years ago

−2x−x+8 please help cant figure it out

Trava [24]

Answer:

-3x+8

Step-by-step explanation:

−2x−x+8

Add the -2x to the -x and you get -3x.

-3x + 8 is the answer if you wrote your equation correctly...

4 0

3 years ago

My brother wants to estimate the proportion of Canadians who own their house.What sample size should be obtained if he wants the

AVprozaik [17]

Answer:

a) $n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

b) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

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

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

The margin of error for the proportion interval is given by this formula:

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

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by: