1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Ne4ueva [31]
3 years ago
6

What was the age distribution of prehistoric Native Americans? Extensive anthropological studies in the southwestern United Stat

es gave the following information about a prehistoric extended family group of 88 members on what is now a Native American reservation. For this community, estimate the mean age expressed in years, the sample variance, and the sample standard deviation. For the class 31 and over, use 35.5 as the class midpoint. (Round your answers to one decimal place.) Age range (years) 1-10 11-20 21-30 31 and over Number of individuals 40 15 23 10
Mathematics
2 answers:
oee [108]3 years ago
7 0

Answer:

revious concepts

In statistics and probability analysis, the expected value "is calculated by multiplying each of the possible outcomes by the likelihood each outcome will occur and then summing all of those values".

The variance of a random variable Var(X) is the expected value of the squared deviation from the mean of X, E(X).

And the standard deviation of a random variable X is just the square root of the variance.  

Solution to the problem

For this case we can calculate the properties required with the following table:

Interval     Mid point (x)     f           x*f         x^2 *f

_________________________________________

1-10               5.5               40        220         1210

11-20             15.5              15        232.5       3603.75

21-30            25.5             23       586.5       14955.75

>31                35.5             10        355          12602.5

________________________________________

Total                                 88        1394         32372

We assume that the mid point for the class >31 is 35.5 using the problem information.

For this case the expected value would be given by:

The variance owuld be given by this formula"

And if we replace we got:

The standard deviation would be just the square root of the variance:

revious concepts

In statistics and probability analysis, the expected value "is calculated by multiplying each of the possible outcomes by the likelihood each outcome will occur and then summing all of those values".

The variance of a random variable Var(X) is the expected value of the squared deviation from the mean of X, E(X).

And the standard deviation of a random variable X is just the square root of the variance.  

Solution to the problem

For this case we can calculate the properties required with the following table:

Interval     Mid point (x)     f           x*f         x^2 *f

_________________________________________

1-10               5.5               40        220         1210

11-20             15.5              15        232.5       3603.75

21-30            25.5             23       586.5       14955.75

>31                35.5             10        355          12602.5

________________________________________

Total                                 88        1394         32372

We assume that the mid point for the class >31 is 35.5 using the problem information.

For this case the expected value would be given by:

The variance owuld be given by this formula"

And if we replace we got:

The standard deviation would be just the square root of the variance:

Step-by-step explanation:

neonofarm [45]3 years ago
4 0

Answer:

\bar X = \frac{\sum_{i=1}^n X_i f_i}{n}= \frac{1394}{88}=15.8

s^2 = \frac{88(32372) -(1394)^2}{88(88-1}=118.3

Sd(X) = \sqrt{118.273}=10.9

Step-by-step explanation:

Previous concepts

In statistics and probability analysis, the expected value "is calculated by multiplying each of the possible outcomes by the likelihood each outcome will occur and then summing all of those values".

The variance of a random variable Var(X) is the expected value of the squared deviation from the mean of X, E(X).

And the standard deviation of a random variable X is just the square root of the variance.  

Solution to the problem

For this case we can calculate the properties required with the following table:

Interval     Mid point (x)     f           x*f         x^2 *f

_________________________________________

1-10               5.5               40        220         1210

11-20             15.5              15        232.5       3603.75

21-30            25.5             23       586.5       14955.75

>31                35.5             10        355          12602.5

________________________________________

Total                                 88        1394         32372

We assume that the mid point for the class >31 is 35.5 using the problem information.

For this case the expected value would be given by:

\bar X = \frac{\sum_{i=1}^n X_i f_i}{n}= \frac{1394}{88}=15.8

The variance owuld be given by this formula"

s^2 = \frac{n(\sum x^2 f) -(\sum xf)^2}{n(n-1}

And if we replace we got:

s^2 = \frac{88(32372) -(1394)^2}{88(88-1}=118.3

The standard deviation would be just the square root of the variance:

Sd(X) = \sqrt{118.273}=10.9

You might be interested in
Factorise x - 2xz - 2xy + 4y². Show all the steps.​
nirvana33 [79]

Answer:

1(x - 2xz - 2xy + 4y²)

Step-by-step explanation:

I notice that no term all of them have. which means itbwill be factorised via 1.

1(x - 2xz - 2xy + 4y²)

3 0
2 years ago
Help me please I need help ASAP
AysviL [449]
The temperature at 10 pm is -3 degrees
3 0
3 years ago
Is r(l+2h) a formula for a length area or volume
Novosadov [1.4K]
Hello,

In my opinion, 
I would say Volume. 

I hope this helps.
4 0
3 years ago
When 4 times the number X is added to 12, the result is 8. What number results when two times x is that at 7?
kow [346]
I think you worded that a little wrong
8 0
3 years ago
marina is paid $28 per hour and works 7 hours per day. she receives one paid day off for each 14 days that she works. what is he
damaskus [11]
We know that

14 days------------> 14*7 hours-----> 98 hours

98 hours*<span>$28 per hour-------> $2744
one paid day-------> </span>$28*7 hours-----> $196<span>

therefore
[</span>her true hourly wage]=[$2744+$196]/(98)-----> $2940/98-----> $30 per hour

the answer is
$30 per hour
8 0
3 years ago
Read 2 more answers
Other questions:
  • What is the answer to (-2)^4=n
    11·2 answers
  • How much greater is 28.95 than 14.25?
    13·1 answer
  • -3x+5y=-9 and 4x+8y=12
    8·2 answers
  • Luke has been saving up his money to
    7·2 answers
  • 4.2y+0.8=6.2y–(1.1y+0.8)+1.2
    15·2 answers
  • (2 1/2+2/5) (5 1/3-16/3)​
    12·1 answer
  • A shade of green paint is made by mixing blue paint and yellow paint in the ratio of 4 to 3. How many pints of blue paint and ye
    11·1 answer
  • fatemeh bought 8 pencils for AED 3 each and 5 black pens for AED 6 each. How much did she pay in the cashier? with unit
    15·1 answer
  • Beth put $8,000 in a savings account. At the end of a year the account had earned $72 in interest. What was the yearly interest
    9·1 answer
  • Someone help me with this still im stock on it plz
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!