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2 years ago

Find the matrix product, if possible.

Mathematics

1 answer:

kondor19780726 [428]2 years ago

3 0

Answer:

below.

Step-by-step explanation:

The number of columns in the first matrix must equal to the number of rows in the second for multiplication to be possible.

Here first matrix has 3 columns and second one has 3 rows so POSSIBLE.

[ -8 2 2] { 3 }

[ 0 ]

[ -3]

= -8*3 + 2*0 + 2 * -3 = [-30] <-------- Answer.

Note a 1*3 matrix multiplied by a 1*3 matrix gives a 1*1 result.

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Suppose that a college determines the following distribution for X = number of courses taken by a full-time student this semeste

lidiya [134]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$ In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$ And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

Step-by-step explanation:

Previous concepts

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

Solution to the problem

For this case we have the following distribution given:

X 3 4 5 6

P(X) 0.07 0.4 0.25 0.28

We can calculate the mean with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$

In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$

And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

3 0

3 years ago

Naomi is 2/3 as tall as her father. If Naomi is 54 inches tall, how tall is her father.

AlekseyPX

Answer:

Her father is 81 inches tall.

Step-by-step explanation:

She is 2/3 as tall as her father so we divide her height by 2. 54/2=27 and then we multiply 27 by three to get 81 inches.

4 0

3 years ago

Read 2 more answers

How many times greater is the 4 in the thousands place compared to the 4 in the hundreds place?

lora16 [44]

It is 10 more in the thousands than the hundreds... multiply 100 x 10...

4 0

3 years ago

Help please here is a picture:

Ivahew [28]

Answer:

Step-by-step explanation:

<u>Mixed Fractions</u>

Mixed fractions are made of an integer part followed by a proper fraction.

Some examples of mixed fractions are:

3 1/2, -4 5/8, 2 2/3

Between two consecutive integers a and a+1, there are infinitely many fractions. The centered number is a 1/2. Any number with its improper fraction part less than 1/2 is closer to a than to a+1.

In our problem, Jayne bought between 2 and 3 pounds of granola. We need to provide a mixed number that is closer to 2 pounds than to 3 pounds.

We can select any number with integer part 2 and a proper fraction less than 1/2.

Examples could be :

2 1/3, 2 1/4, 2 3/7

All of them are less than 2.5

6 0

3 years ago

Jay has an album that holds 500 hockey cards. Each page of the album holds 5 hockey cards. If 17% of the album is empty, how m

tamaranim1 [39]

Answer: 83

Step-by-step explanation: 17% of 500 is 85. If 17% is empty, that means that you'd take away that 15%. 500 - 85 = 415. If each page holds 5 cards, we need to split those cards up between the pages. 415/5 = 83, so 83 pages will be used.

5 0

3 years ago