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3 years ago

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12.1.33 Question Help Suppose that 62% of families living in a certain country own an HDTV and 16% own a computer. The Additio

n Rule might suggest, then, that 78% of families own either an HDTV or a computer. What's wrong with that reasoning?

1 answer:

poizon [28]3 years ago

6 0

Answer:

Step-by-step explanation:

Suppose :

62% own an HDTV

16% own a computer

Using the addition rule : suggests that (62% + 16%) = 78% either own an HDTV or a computer.

The reasoning is wrong because ; since it is possible to own both an HDTV and also own a computer at the same time, the outcome of the addition rule is wrong as both events are independent. If both event cannot occur at the same time (mutually exclusive event) , then, the addition rule may be applied,. But since both can occur independently and each family can own an HDTV while also owning a computer, then the addition rule is wrong for the scenario described.

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Two major automobile manufacturers have produced compact cars with engines of the same size. We are interested in determining wh

Molodets [167]

Answer:

(A) The mean for the differences is 2.0.

(B) The test statistic is 1.617.

(C) At 90% confidence the null hypothesis should not be rejected.

Step-by-step explanation:

We are given that a random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance.

The following data (in miles per gallon) show the results of the test;

Driver Manufacturer A Manufacturer B

1 32 28

2 27 22

3 26 27

4 26 24

5 25 24

6 29 25

7 31 28

8 25 27

Let $\mu_1$ = mean MPG for the fuel efficiency of Manufacturer A brand

$\mu_2$ = mean MPG for the fuel efficiency of Manufacturer B brand

SO, Null Hypothesis, $H_0$ : $\mu_1-\mu_2=0$ or $\mu_1= \mu_2$ {means that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles}

Alternate Hypothesis, $H_A$ : $\mu_1-\mu_2\neq 0$ or $\mu_1\neq \mu_2$ {means that there is a significant difference in the mean MPG (miles per gallon) for the fuel efficiency of these two brands of automobiles}

The test statistics that will be used here is <u>Two-sample t test statistics</u> as we don't know about the population standard deviations;

T.S. = $\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }$ ~ $t__n__1+_n__2-2$

where, $\bar X_1$ = sample mean MPG for manufacturer A = $\frac{\sum X_A}{n_A}$ = 27.625

$\bar X_2$ = sample mean MPG for manufacturer B = $\frac{\sum X_B}{n_B}$ = 25.625

$s_1$ = sample standard deviation for manufacturer A = $\sqrt{\frac{\sum (X_A-\bar X_A)^{2} }{n_A-1} }$ = 2.72

$s_2$ = sample standard deviation manufacturer B = $\sqrt{\frac{\sum (X_B-\bar X_B)^{2} }{n_B-1} }$ = 2.20

$n_1$ = sample of cars selected from manufacturer A = 8

$n_2$ = sample of cars selected from manufacturer B = 8

Also, $s_p=\sqrt{\frac{(n_1-1)s_1^{2}+(n_2-1)s_2^{2} }{n_1+n_2-2} }$ = $\sqrt{\frac{(8-1)\times 2.72^{2}+(8-1)\times 2.20^{2} }{8+8-2} }$ = 2.474

(A) The mean for the differences is = 27.625 - 25.625 = 2

(B) <u><em>The test statistics</em></u> = $\frac{(27.625-25.625)-(0)}{2.474 \times \sqrt{\frac{1}{8}+\frac{1}{8} } }$ ~ $t_1_4$

= 1.617

(C) Now at 10% significance level, the t table gives critical values between -1.761 and 1.761 at 14 degree of freedom for two-tailed test. Since our test statistics lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u>we fail to reject our null hypothesis</u>.

Therefore, we conclude that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles.

5 0

4 years ago

Help me with this please. :(

Digiron [165]

Answer:

I think - 11 Is a negative number that is why it is an integer number maybe whole number also

3 0

3 years ago

Complete this table to show the sample space for each roll in the game

leva [86]

I'm assuming you only need help with part B. If that's the case, then all we do is add up the values outside of the table to get the inner cell results. For example, in row 1, column 1, we have 1's outside. They add to 1+1 = 2. So we'll have 2 in the first row and first column of the table. The other cells are computed in this way. In figure 1 (see attached image), I show the intermediate step of adding. Then in figure 2, I actually add up the values and show the final result of what the table will look like when all said and done. Take note of the color coding to help see how the values match up for each inner cell of the table. The color coding is optional.

------------------------------------------------------------------------------------------------------------

Edit:

Part C -- Part 1) Probability of rolling double sixes

There are five copies of "6" in the table (see figure 2 of the attached image) out of 36 total possibilities. How did I get 36? It's the result of multiplying 6*6. This is because there are 6 faces per die. As the table shows, there are 6 rows and 6 columns giving 36 cells total.

So we divide the number of times "6" shows up (5 times) out of the number of total possibilities (36 total) to get: 5/36 = 0.1389 = 13.89%

Answer as a fraction: 5/36

Answer as a decimal: 0.1389

Answer as a percent: 13.89%

The decimal and percent forms are approximate

---------------------------------------------

Part C -- Part 2) Probability of rolling doubles

To roll doubles, all we need to do is roll the same number twice on each die. In other words, we have "twin values" so to speak. Back in part 1 above, we dealt with just '6's showing up twice. There are other doubles as well

The doubles possibilities are:

1 and 1

2 and 2

3 and 3

4 and 4

5 and 5

6 and 6

Each combo listed above only shows up once. So we have 6 instances where we have doubles (one instance per side of the die). This is out of 36 total

Divide the values mentioned: 6/36 = 1/6 = 0.1667 = 16.67%

Answer as a fraction: 1/6

Answer as a decimal: 0.1667

<span>Answer as a percent: 16.67%</span>

The decimal and percent forms are approximate

7 0

3 years ago

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Marat540 [252]

40 * 7.85 = 314

32.24 + 24.02 + 24.53 = 80.79

314 - 80.79 = 233.21

Answer is D

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4 years ago

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olga2289 [7]

Answer:

sqrt25

Step-by-step explanation:

Step-By-Step explanation

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