Ask question

Ask question

All categories

3 years ago

11

729 students attend Penny Creek Elementary. Yesterday, 63 students were on a field trip to the zoo. 18 students were home sick.

How many students were in class?

1 answer:

trasher [3.6K]3 years ago

5 0

Answer:

648

Step-by-step explanation:

You might be interested in

A true-false quiz with 10 questions was given to a statistics class. Following is the probability distribution for the score of

disa [49]

Answer:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

Step-by-step explanation:

For this case we assume the following probability distribution:

X 5 6 7 8 9 10

P(X) 0.05 0.15 0.33 0.28 0.12 0.07

First we need to find the expected value (first moment) and the second moment in order to find the variance and then the standard deviation.

In order to calculate the expected value we can use the following formula:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

In order to find the standard deviation we need to find first the second moment, given by :

$E(X^2)=\sum_{i=1}^n X^2_i P(X_i)$

And using the formula we got:

$E(X^2)=(5^2 *0.05)+(6^2 *0.15)+(7^2 *0.33)+(8^2 *0.28)+ (9^2 *0.12 +(10^2 *0.07))=57.46$

Then we can find the variance with the following formula:

$Var(X)=E(X^2)-[E(X)]^2 =57.46-(7.48)^2 =1.5096$

And then the standard deviation would be given by:

$Sd(X)=\sqrt{Var(X)}=\sqrt{1.5096}=1.229$

5 0

4 years ago

Read 2 more answers

I need help with my homework please?Anna can buy 3 sweatshirts for a total of $45. How much would it cost if she were to buy 5 s

Reptile [31]

Nine dollars per sweatshirt (5) in total 45

6 0

3 years ago

Whats the domain of the graph of the function

zavuch27 [327]

Answer:

[-5, 7]

Step-by-step explanation:

6 0

3 years ago

1. A Square shaped wooden plate has a diagonal length of 30cm. Can you find the Perimeter of plate ?

DerKrebs [107]

Answer:

84.85cm

Step-by-step explanation:

Let the sides of the square be x

The perimeter of the square = 4x

Get x using the pythagoras theorem

x^2 + x^2 = 30^2

2x^2 = 900

x^2 = 450

x = 21.21cm

Perimeter of the plate = 4(21.21)

Perimeter of the plate = 84.85cm

6 0

3 years ago

32 gal/min = what qt/h

mafiozo [28]

32g/m = 32*60 = 1920 gallons per hour

1 gallon = 4 quarts

1920 *4 = 7680 quarts per hour

3 0

3 years ago

Read 2 more answers