A frozen dinner at a grocery store is purchased for $2.20 wholesale and is marked up by 40 percent. A customer wants to buy four
2 answers:
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Answer:
The test statistic value is 15.3.
Step-by-step explanation:
The hypothesis for this test is:
<em>H</em>₀: The average number of homeless people is not increasing, i.e. <em>μ</em> = 42.3.
<em>H</em>ₐ: The average number of homeless people is increasing, i.e. <em>μ</em> > 42.3.
Given:
As the population standard deviation is provided use a single mean <em>z</em>-test for the hypothesis testing.
The test statistic is:
Thus, the test statistic value is 15.3.
Answer:
The probability that exactly 97 of them finished the marathon is 0.221.
Step-by-step explanation:
We are given that in 2019, approximately 97.4% of all the runners who started the Boston Marathon were able to complete the 42.2 km race.
100 runners are chosen at random.
The above situation can be represented through the binomial distribution;
where, n = number of trials(or samples) taken = 100 runners
r = number of success = exactly 97
p = probability of success which in our question is the probability
that runners finished the marathon, i.e; p = 0.974
So, X ~ Binom(n = 100, p = 0.974)
Now, the probability that exactly 97 of them finished the marathon is given by = P(X = 97)
P(X = 97) =
=
= 0.221
Hence, the required probability is 0.221.
Answer:
Step-by-step explanation:
Hello!
The variable of interest is
X: The number of emergency service calls made by the volunteer ambulance service of Walterboro, South Carolina for 50 days.
a)
In the first column, you have the possible number of emergency calls made, in the second column, you have the observed absolute frequency (fi) for each value of the variable.
To establish the probability distribution you have to calculate the relative frequency (hi) for each value of X.
The formula for the relative frequency is
hi= fi*n where i= 0, 1, 2, 3, 4
X₁= 0
f₁= 8
h₁= 8/50= 0.16
X₂= 1
f₂= 10
h₂= 0.20
X₃= 2
f₃= 22
h₃= 22/50= 0.44
X₄= 3
f₄= 9
h₄= 9/50= 0.18
X₅= 4
f₅= 1
h₅= 1/50= 0.02
(See attachment)
b)
The variable of interest is a cuantitative discrete variable, so this is an example of a driscrete distribution.
Discrete variables are numerical and take certain numbers within its range of definition, contrary to the continuous variables that can take any value within the range of definition of the variable.
Another example of a discrete variable is "the money", If the variable is "I have at most 10 dollars in my wallet", the range of definition goes from 0 dollars to 10 dollars.
c) To calculate the mean when the data is arranged in a frequency table you have to use the following formula:
X[bar]= ∑Xihi= (0*0.16)+(1*0.2)+(2*0.44)+(3*0.18)+(4*0.02)= 1.7
This means that they expect an average of 1.7 calls per day.
d) The formula for the standard deviation is:
∑X²fi= (0²*8)+(1²*10)+(2²*22)+(3²*9)+(4²*1)= 195
∑Xfi= (0*8)+(1*10)+(2*22)+(3*9)+(4*1)= 85
I hope this helps!
