How many ways can 11 photographs be arranged horizontally

A Washington, D.C., "think tank" announces the typical teenager sent 67 text messages per day in 2017. To update that estimate,

creativ13 [48]

Answer:

We reject the null hypothesis and fail to accept it and update that estimate that typical teenager sent does not 67 text messages per day.

Step-by-step explanation:

We are given the sample:

51, 175, 47, 49, 44, 54, 145, 203, 21, 59, 42, 100

Formula:

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

$Mean =\displaystyle\frac{990}{12} = 82.5$

Sum of squares of differences = 992.25 + 8556.25 + 1260.25 + 1122.25 + 1482.25 + 812.25 + 3906.25 + 14520.25 + 3782.25 + 552.25 + 1640.25 + 306.25 = 3539.363636

$S.D = \sqrt{\frac{3539.363636}{11}} = 59.5$

We are given the following in the question:

Population mean, μ =67

Sample mean, $\bar{x}$ = 82.5

Sample size, n = 12

Alpha, α = 0.05

Sample standard deviation, s = 59.5

First, we design the null and the alternate hypothesis

$H_{0}: \mu = 67\\H_A: \mu > 67$

We use One-tailed t test to perform this hypothesis.

b) Formula:

$t_{stat} = \displaystyle\frac{\bar{x} - \mu}{\frac{s}{\sqrt{n-1}} }$

Putting all the values, we have

$t_{stat} = \displaystyle\frac{82.5 - 67}{\frac{59.5}{\sqrt{11}} } = 0.864$ Now,

$t_{critical} \text{ at 0.05 level of significance, 11 degree of freedom } = 1.795$

a) Since,

$t_{stat} < t_{critical}$

We reject the null hypothesis and fail to accept it and update that estimate that typical teenager send more than 67 text messages per day.

5 0

2 years ago

Jillana takes a single dose of medication that remains in her body according to the equation r = 200(0.75)d, where r represents

grin007 [14]

I looked at another online and it said letter A. (Not 100% sure)

7 0

2 years ago

a concrete company is pouring concrete into a triangular form as the center of a new playground. the foreman measures the triang

Gemiola [76]

Answer:

Equilateral type of Triangle is created.

Step-by-step explanation:

Incenter: It is a point of intersection of angle bisector of three angles of a triangle.

Circumcenter: It is a point of intersection of perpendicular bisector of three sides of a triangle.

For an Equilateral Triangle points incenter and circumcenter must coincide (same). Hence the type is Equilateral Triangle

4 0

2 years ago

Aramp is 17 feet long, rises 8 feet above the floor, and covers a horizontal distance of 15 feet, as shown in the figure.

bonufazy [111]

Answer:

The ratio of Tan B is

$\tan B= \dfrac{AC}{BC}=\dfrac{8}{15}$

OR

$\tan A= \dfrac{BC}{AC}=\dfrac{15}{8}$

Step-by-step explanation:

In Right Angle Triangle ABC

angle C = 90°

AB = Ramp = 17 feet

BC =Horizontal distance = 15 feet

AC = Height from floor = 8 feet

To Find:

Ratio of Tan B = ?

Solution:

In Right Angle Triangle ABC By Tangent Identity we have

$\tan B= \dfrac{\textrm{side opposite to angle B}}{\textrm{side adjacent to angle B}}$

Substituting the given values we get

$\tan B= \dfrac{AC}{BC}=\dfrac{8}{15}$

OR

$\tan A= \dfrac{BC}{AC}=\dfrac{15}{8}$

5 0

2 years ago

One box of crackers costs $1.75. The crackers are advertised as “3 boxes for $5.25.” Which proportion can be used to represent t

Daniel [21]

A. 1/1.75 = 3/5.25

Ignore this part I'm just trying to get at least 20 characters.

5 0

2 years ago

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