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3 years ago

The product of twenty one negative integers is negative? True of false

1 answer:

5 0

A negative number once is negative. Multiplied by another negative number, it's positive. Multiply that positive number by a negative number, and you have a negative number again. Repeating that pattern, with odd numbers being negative, it is true

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Finding product for 4 digit numbers

Amanda [17]

One answer would be15669012

7 0

3 years ago

Which shapes are congruent? (See attachment)

Andre45 [30]

Hello! Congruent figures are those with the same size and shape. With that being said, if you look at the shapes correctly, here are your answers:

Quad 1 & 2: Not Congruent
Quad 1 & 3: Congruent
Quad 1 & 4: Congruent
Quad 2 & 3: Not Congruent
Quad 2 & 4: Not Congruent
Quad 3 & 4: Congruent

3 0

3 years ago

Read 2 more answers

A statistics student wants to compare his final exam score to his friend's final exam score from last year; however, the two exa

yarga [219]

Answer:

$z= \frac{85-70}{10}=1.5$

$z= \frac{45-35}{5}=2$

So then the correct answer for this case is:

B) Our student, Z= 1.50; his friend, Z=2.00.

Step-by-step explanation:

Assuming this complete question:

A statistics student wants to compare his final exam score to his friend's final exam score from last year; however, the two exams were scored on different scales. Remembering what he learned about the advantages of Z scores, he asks his friend for the mean and standard deviation of her class on the exam, as well as her final exam score. Here is the information:

Our student: Final exam score = 85; Class: M = 70; SD = 10.

His friend: Final exam score = 45; Class: M = 35; SD = 5.

The Z score for the student and his friend are:

A) Our student, Z= -1.07; his friend, Z= -1.14.

B) Our student, Z= 1.50; his friend, Z=2.00.

C) Our student, Z= 1.07; his friend, Z= -1.14.

D) Our student, Z= 1.07; his friend, Z= 1.50

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution

Let X the random variable that represent the scores for our student, and for this case we know that:

$E(X)= \mu =70, SD_X=\sigma=10$

The z score is given by:

$z=\frac{x-\mu}{\sigma}$

If we use this we got:

$z= \frac{85-70}{10}=1.5$

Let Y the random variable that represent the scores for his friend, and for this case we know that:

$E(Y)= \mu =35, SD_Y=\sigma=5$

The z score is given by:

$z=\frac{y-\mu}{\sigma}$

If we use this we got:

$z= \frac{45-35}{5}=2$

So then the correct answer for this case is:

B) Our student, Z= 1.50; his friend, Z=2.00.

3 0

3 years ago

3. Last year, the numbers of calculators produced per day at a certain factory were normally distributed with a mean of 560 calc

Mademuasel [1]

Answer:

3. Last year, the numbers of calculators produced per day at a certain factory were normally distributed with a mean of 560 calculators and a standard deviation of 12 calculators.(C)

Step-by-step explanation:

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8 0

3 years ago

If the length of the minute hand of the clock in London commonly known as “Big Ben” is 11.25’ from the center of the clock to th

rodikova [14]

First, we should figure out the area of the entire face of the clock because we need that information to solve the problem. The formula for the area of a circle is A=pi*r^2. Since we know that r (radius) is equal to 11.25 feet, we can plug this in for r and solve for A: A=pi*11.25^2 which equals A=397.61 ft^2 rounded to the nearest hundredth.

Now, to find the area the hand sweeps over in 5 minutes, we should determine how much of the clock the hand sweeps over in 5 minutes. Think about it like this: since 5 minutes goes into 60 minutes 12 times (60/5=12), then 5 minutes is one twelfth of the clock's face. Therefore, we are going to divide the total area by 12 (397.61/12) to get 33.13 ft^2, so the answer is C.

I hope this helps.

5 0

3 years ago