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2 years ago

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A town planner is interested in getting some demographic data about the households in the city. The city has four wards with the

following numbers of households: ward A has 2,107, ward B has 903, ward C has 1,505, and ward D has 1,499. The budget for the project allows the planner to survey 100 households. She plans to use a stratified sampling method. How many households should be chosen from ward B? Enter a whole number.

1 answer:

UkoKoshka [18]2 years ago

4 0

Answer:

15

Step-by-step explanation:

Population size= 2107+903+1505+1499

= 6014

Calculating the sample of ward B by using the stratified random sampling formula:

Stratified Random Sample, np= ( Np / N ) * n

where

np= pth stratum sample size

Np= pth stratum population size

N = population size

n = sample size

Stratified Sample (ward B) = 100 / 6014 * 903 = 15 !

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The owners of Prim's Pizza are concerned that many of their customers are starting to purchase pizza from The Pizza Palace becau

AleksandrR [38]

Answer:

$(240-210) -1.984 \sqrt{\frac{8.6^2}{100}+\frac{5.7^2}{100}}=27.953$

$(240-210) +1.984 \sqrt{\frac{8.6^2}{100}+\frac{5.7^2}{100}}=32.047$

And the confidence interval for the difference is between:

$27.953 \leq \mu_1 -\mu_2 \leq 32.047$

Step-by-step explanation:

We have the following info given:

$\bar X_1 = 240$ sample mean for medium Pizzas from Prim's

$\bar X_2 = 210$ sample mean for medium Pizzas from Pizza Place

$s_1 =8.6$ sample deviation for Prim's

$s_2 =5.7$ sample deviation for Pizza Palca

$n_1 =n_2 = 100$ sample size selected for each case

The confidence interval for the difference of means is given by:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2}\sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}$

And for the 95% confidence we need a significance level of $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ , the degrees of freedom are given by:

$df= n_1 +n_2 -2= 100+100-2 =98$

And the critical value would be

$t_{\alpha/2}= 1.984$

And replacing we got:

$(240-210) -1.984 \sqrt{\frac{8.6^2}{100}+\frac{5.7^2}{100}}=27.953$

$(240-210) +1.984 \sqrt{\frac{8.6^2}{100}+\frac{5.7^2}{100}}=32.047$

And the confidence interval for the difference is between:

$27.953 \leq \mu_1 -\mu_2 \leq 32.047$

8 0

2 years ago

The word geometry has eight letters. three letters are chosen at random. what is the probability that two consonants and one vow

olga nikolaevna [1]

Answer:

0.536 is the required probability.

Step-by-step explanation:

We have been given the word the word "GEOMETRY"

we have to find the probability that two consonants and one vowel are chosen:

Number of consonants are: 5

Number of vowels are: 3

Hence, The required probability is: $\frac{^5C_2\cdot ^3C_1}{^8C_3}$

Using: $^nC_r=\frac{n!}{(r!)(n-r)!}$

$\frac{\frac{5!}{3!\cdot 2!}\cdot\frac{3!}{1!\cdot 2!}}{\frac{8!}{3!\cdot 5!}}$

Simplifying the above expression:

$\frac{\frac{5\cdot 4\cdot 3!}{3!\cdot 2}\cdot {\frac{3\cdot 2!}{2!}}}{\frac{8\cdot 7\cdot 6\cdot 5!}{5!\cdot 3\cdot 2}}$

Further simplification after cancelling out the common terms we get:

$\Rightarrow \frac{30}{56}=\frac{15}{28}=0.5357=0.536$

Hence, Option 1 is correct.

4 0

2 years ago

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11. The sales tax rate is 6.9%

Norma-Jean [14]

Answer:

40.1%

Step-by-step explanation:

I am assuming that 192 is in 100%.

100% = 192

I then represent the value that we are looking for with $x$ .

x% = 77

By dividing both equations (100% = 192 and x% = 77) and remembering that both left hand sides of BOTH equations have the percentage unit (%).

$\frac{100}{x} = \frac{77}{192}$

Now, of course, we take the reciprocal, or inverse, of both sides:

$\frac{x}{100} = \frac{7}{192}$

x = 40.1%

Thus making the answer: 40.1% of 192 is 77.

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2 years ago

According to the Rational Root Theorem, what are all the potential rational roots of f(x) = 15x11 – 6x8 + x3 – 4x + 3?

scoundrel [369]

we have

$f(x) = 15x^{11} -6x^{8} + x^{3} - 4x + 3$

we know that

<u>The Rational Root Theorem</u> states that when a root 'x' is written as a fraction in lowest terms

$x=\frac{p}{q}$

p is an integer factor of the constant term, and q is an integer factor of the coefficient of the first monomial.

So

in this problem

the constant term is equal to $3$

and the first monomial is equal to $15x^{11}$ -----> coefficient is $15$

So

possible values of p are $1, and\ 3$

possible values of q are $1, 3, 5, and\ 15$

therefore

<u>the answer is</u>

The all potential rational roots of f(x) are

(+/-) $\frac{1}{15}$ ,(+/-) $\frac{1}{5}$ ,(+/-) $\frac{1}{3}$ ,(+/-) $\frac{3}{5}$ ,(+/-) $1$ ,(+/-) $3$

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2 years ago

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The commission earned on the sale of a car can be represented by the equation c(p)=250+0.02p where c represents the commission a

ch4aika [34]

Answer:

1) His total commission is $1,234.3

2) The purchase of the car is $24,790.

Step-by-step explanation:

1) 21640*0.02= 432.8+ 250= 682.8

15075*0.02= 301.5+ 250= 551.5

682.8+ 551.5= 1,234.3

2) 745.8- 250= 495.8/ 0.02= 24,790

6 0

2 years ago

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