Graph f(x) = 2 sin x.<br> Use 3.14 for π.

Exhibit: Department Store.

aalyn [17]

Answer:

Step-by-step explanation:

Considering the central limit theorem, the distribution is normal since the number of samples is large.

Confidence interval is written in the form,

(Sample mean - margin of error, sample mean + margin of error)

The sample mean, x is the point estimate for the population mean.

Confidence interval = mean ± z × σ/√n

Where

σ = population standard Deviation

σ/√n = sample standard deviation

Confidence interval = x ± z × σ/√n

1) x = $75

σ = $24

To determine the z score, we subtract the confidence level from 100% to get α

α = 1 - 0.96 = 0.04

α/2 = 0.04/2 = 0.02

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.02 = 0.98

The z score corresponding to the area on the z table is 2.05. Thus, confidence level of 96% is 2.05

Confidence interval = 75 ± 2.05 × 24/√64

= 75 ± 2.05 × 3

= 75 ± 6.15

The lower end of the confidence interval is

75 - 6.15 = 68.85

The upper end of the confidence interval is

75 + 6.15 = 81.15

2) n = 400

x = $75

σ = $24

z = 2.05

Confidence interval = 75 ± 2.05 × 24/√400

= 75 ± 2.05 × 1.2

= 75 ± 2.46

The lower bound of the confidence interval is

75 - 2.46 = 72.54

The upper bound of the confidence interval is

75 + 2.46 = 77.46

3) n = 400

x = $200

σ = $80

The z score corresponding to the confidence level of 94% is 1.88

z = 1.88

Confidence interval = 200 ± 1.88 × 80/√400

= 200 ± 1.88 × 4

= 200 ± 7.52

Margin of error = 7.52

7 0

3 years ago

a 64 gallon tank contains 45 gallons of oil. How many gallons are removed if 4/5 of this quantity is sold?

skad [1K]

4/5 is already simplified so its going to be 4/5 or .45

6 0

3 years ago

Round to the nearest hundredth. 20 POINTS<br> 4.776<br> and brainiest.

Tanzania [10]

Answer:

4.7

any questions?

7 0

2 years ago

Read 2 more answers

Which function is the same as y = 3 cosine (2 (x startfraction pi over 2 endfraction)) minus 2? y = 3 sine (2 (x startfraction p

kirza4 [7]

The function which is same as the function y = 3cos(2(x +π/2)) -2 is: Option A: y= 3sin(2(x + π/4)) - 2

<h3>How to convert sine of an angle to some angle of cosine?</h3>

We can use the fact that:

$\sin(\theta) = \cos(\pi/2 - \theta)\\\sin(\theta + \pi/2) = -\cos(\theta)\\\cos(\theta + \pi/2) = \sin(\theta)$

to convert the sine to cosine.

<h3>Which trigonometric functions are positive in which quadrant?</h3>

In first quadrant (0 < θ < π/2), all six trigonometric functions are positive.
In second quadrant(π/2 < θ < π), only sin and cosec are positive.
In the third quadrant (π < θ < 3π/2), only tangent and cotangent are positive.
In fourth (3π/2 < θ < 2π = 0), only cos and sec are positive.

(this all positive negative refers to the fact that if you use given angle as input to these functions, then what sign will these functions will evaluate based on in which quadrant does the given angle lies.)

Here, the given function is:

$y= 3\cos(2(x + \pi/2)) - 2$

The options are:

$y= 3\sin(2(x + \pi/4)) - 2$
$y= -3\sin(2(x + \pi/4)) - 2$
$y= 3\cos(2(x + \pi/4)) - 2$
$y= -3\cos(2(x + \pi/2)) - 2$

Checking all the options one by one:

Option 1: $y= 3\sin(2(x + \pi/4)) - 2$

$y= 3\sin(2(x + \pi/4)) - 2\\y= 3\sin (2x + \pi/2) -2\\y = -3\cos(2x) -2\\y = 3\cos(2x + \pi) -2\\y = 3\cos(2(x+ \pi/2)) -2$

(the last second step was the use of the fact that cos flips its sign after pi radian increment in its input)
Thus, this option is same as the given function.

Option 2: $y= -3\sin(2(x + \pi/4)) - 2$

This option if would be true, then from option 1 and this option, we'd get:
$-3\sin(2(x + \pi/4)) - 2= -3\sin(2(x + \pi/4)) - 2\\2(3\sin(2(x + \pi/4))) = 0\\\sin(2(x + \pi/4) = 0$