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3 years ago

4s*2+7s+2=0 Quadratic formula

Mathematics

1 answer:

natita [175]3 years ago

6 0

Answer:

z=−215z=-215

Step-by-step explanation:

z=−215z=-215

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According to a research center, 16% of all merchandise sold in a particular country gets returned. A department store in a certa

Mamont248 [21]

Answer:

a) point estimate of the proportion of items returned for the population of sales transactions at the store in the given city

Point estimate = 0.3

b) The 95% confidence interval for the proportion of returns at the store in the given city

( 0.19958,0.40042)

Step-by-step explanation:

Given the Population proportion 'P'= 16% = 0.16

Given data a department store in a certain city sampled 80 items sold in January and found that 24 of the items were returned

The sample proportion $p = \frac{x}{n}$

here x =24 and n = 80

The sample proportion $p = \frac{x}{n} = \frac{24}{80} = 0.3$

a) Point estimate:-

A point estimate of the true proportion P

Point estimate = $p = \frac{x}{n}$

point estimate of the proportion of items returned for the population of sales transactions at the store in the given city

$p = \frac{x}{n} = \frac{24}{80} = 0.3$

b) The 95% confidence interval for the proportion

The 95% confidence interval for the proportion of returns at the store in the given city

$(p - z_{\alpha } \sqrt{\frac{p(1-p)}{n} } , p + z_{\alpha }\sqrt{\frac{p(1-p)}{n} } )$

substitute all values we get ,

$(0.3 - 1.96 \sqrt{\frac{0.3(1-0.3)}{80} } , 0.3 + 1.96\sqrt{\frac{0.3(1-0.3)}{80} } )$

on simplification, we get

(0.3-0.10042 ,0.3+0.10042)

( 0.19958,0.40042)

Conclusion:-

a) point estimate of the proportion of items returned for the population of sales transactions at the store in the given city

Point estimate = 0.3

b) The 95% confidence interval for the proportion of returns at the store in the given city

( 0.19958,0.40042)

5 0

4 years ago

A pot of stew is placed on a stove to heat. The temperature of the liquid reaches 170°F, and then the pot is taken off the burne

belka [17]

Answer:

$T =84.7\°F$

Step-by-step explanation:

Newton's cooling model is:

$T(t) =T_0 + (T_i-T_0)e^{-kt}$

Where

t is the time in hours

$T_0$ is the ambient temperature

$T_i$ is the initial temperature of the body

$k=0.34$

We know that:

$T_0=76\°F$

$T_i=170\°F$

Then after 7 hours the temperature of the liquid will be:

$T(7) =76 + (170-76)e^{-0.34(7)}$

$T =84.7\°F$

7 0

3 years ago

What is the area of the figure?

Vikentia [17]

1) Striangle = 1/2 * (12-8) * 4 = 1/2 * 4 * 4 = 8 km^2

2) Srectangle = 4 * 8 = 32 km^2

3) Sfigure = 8 + 32 = 40 km^2

Number C

4 0

4 years ago

Any help is appreciated

Katarina [22]

Answer:

2 units because there is no change in size.

5 0

4 years ago

Eleven more than four times a number is 23

goblinko [34]

3 is the original number
You have to do reverse operations
23-11=12
12/4=3

7 0

3 years ago