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ICE Princess25 [194]

2 years ago

5

A poll of 1700 randomly selected students in grades 6 through 8 was conducted and found that 53% enjoy playing sports. is the 53

% result a statistic or a parameter? explain.

1 answer:

Jet001 [13]2 years ago

8 0

This is a statistic, because it describes a sample.

A parameter describes a population.

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(43 points) In the US, 85% of the population has Rh positive blood. Suppose we take a random sample of 6 persons and let Y denot

VladimirAG [237]

Answer:

a) Binomial distribution with parameters p=0.85 q=0.15 n=6

b) 62.29%

c) 2.38%

d) See explanation below

Step-by-step explanation:

a)

We could model this situation with a binomial distribution

$P(6;k)=\binom{6}{k}p^kq^{6-k}$

where P(6;k) is the probability of finding exactly k people out of 6 with Rh positive, p is the probability of finding one person with Rh positive and q=(1-p) the probability of finding a person with no Rh.

So

$\bf P(Y=k)=\binom{6}{k}(0.85)^k(0.15)^{6-k}$

b)

The probability that Y is less than 6 is

P(Y=0)+P(Y=1)+...+P(Y=5)

Let's compute each of these terms

$P(Y=0)=P(6;0)=\binom{6}{0}(0.85)^0(0.15)^{6}=1.139*10^{-5}$

$P(Y=1)=P(6;1)=\binom{6}{1}(0.85)^1(0.15)^{5}=0.0000387281$

$P(Y=2)=P(6;2)=\binom{6}{2}(0.85)^2(0.15)^{4}=0.005486484$

$P(Y=3)=P(6;3)=\binom{6}{3}(0.85)^3(0.15)^{3}=0.041453438$

$P(Y=4)=P(6;4)=\binom{6}{4}(0.85)^4(0.15)^{2}=0.176177109$

$P(Y=5)=P(6;5)=\binom{6}{5}(0.85)^5(0.15)^{1}=0.399334781$

and adding up these values we have that the probability that Y is less than 6 is

$\sum_{i=1}^{5}P(Y=i)=0.622850484\approx 0.6229=62.29\%$

c)

In this case is a binomial distribution with n=200 instead of 6.

p and q remain the same.

The mean of this sample would be 85% of 200 = 170.

In a binomial distribution, the standard deviation is

$s = \sqrt{npq}$

In this case

$\sqrt{200(0.85)(0.15)}=5.05$

<em>Let's approximate the distribution with a normal distribution with mean 170 and standard deviation 5.05</em>

So, the approximate probability that there are fewer than 160 persons with Rh positive blood in a sample of 200 would be the area under the normal curve to the left of 160

(see picture attached)

We can compute that area with a computer and find it is

0.0238 or 2.38%

d)<em> In order to approximate a binomial distribution with a normal distribution we need a large sample like the one taken in c).</em>

In general, we can do this if the sample of size n the following inequalities hold:

$np\geq 5 \;and\;nq \geq 5$

in our case np = 200*0.85 = 170 and nq = 200*0.15 = 30

4 0

3 years ago

Michaela is planning a pizza party for 48 people. she has $200 to buy pizza and soda for the party. Each 12-pack of soda can cos

Dominik [7]

The answer to this question would be: D. <span>200>6P(8.00)+4S(5.00)
</span>

Michaela is planning a pizza party for 48 people and she uses 12-pack of soda and <span>8-slice pizza. That means the pack of soda she needs would be:
48 people/ (12soda/pack)= 4 pack

Then, number the pizza she needs:
48 people/ 8 (slice/pizza)= 6 pizza

She has $200 so the price she can afford should be lower than that. The function would be:
the money she has > number of pizza(price of pizza) + number of soda(price of soda)
</span>200>6P(8.00)+4S(5.00)

7 0

3 years ago

Read 2 more answers

Question 1: Assume that y varies inversely with x. If y=9 when x=7, find y when x=2. Enter in any fractions using a / (e.g. "1/2

oksano4ka [1.4K]

Answer:

3

Step-by-step explanation:

trust me

6 0

3 years ago

What is formed when two complementary angles share one ray?

aleksklad [387]

Answer:

B.

the complementary angles form a right angle with the shared ray

5 0

2 years ago

What is the slope for y=-5x-6

olga_2 [115]

Answer:

-5 is the slope and -6 is the y intercept

Step-by-step explanation:

This is in the form

y =mx+b where m is the slope and b is the y intercept

y = -5x -6

-5 is the slope and -6 is the y intercept

3 0

3 years ago