Salmon Weights: Assume that the weights of spawning Chinook salmon in the Columbia river are normally distributed. You randomly catch and weigh 17 such salmon. The mean weight from your sample is 19.2pounds with a standard deviation of 4.4 pounds. You want to construct a 90% confidence interval for the mean weight of all spawning Chinook salmon in the Columbia River.(a) What is the point estimate for the mean weight of all spawning Chinook salmon in the Columbia River?
pounds
(b) Construct the 90% confidence interval for the mean weight of all spawning Chinook salmon in the Columbia River. Round your answers to 1 decimal place.
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(c) Are you 90% confident that the mean weight of all spawning Chinook salmon in the Columbia River is greater than 18 pounds and why?
No, because 18 is above the lower limit of the confidence interval.
Yes, because 18 is below the lower limit of the confidence interval.
No, because 18 is below the lower limit of the confidence interval.
Yes, because 18 is above the lower limit of the confidence interval.
(d) Recognizing the sample size is less than 30, why could we use the above method to find the confidence interval?
Because the sample size is greater than 10.
Because we do not know the distribution of the parent population.
Because the parent population is assumed to be normally distributed.
Because the sample size is less than 100.
Answers
Answer:
a) represent the sample mean. And that represent the best estimator for the population mean since
b) The 90% confidence interval is given by (17.3;21.1)
c) No, because 18 is above the lower limit of the confidence interval.
d) Because the parent population is assumed to be normally distributed.
The reason of this is because the t distribution is an special case of the normal distribution when the degrees of freedom increase.
Step-by-step explanation:
1) Notation and definitions
n=17 represent the sample size
Part a
represent the sample mean. And that represent the best estimator for the population mean since
Part b
represent the sample standard deviation
m represent the margin of error
Confidence =90% or 0.90
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
2) Calculate the critical value tc
In order to find the critical value is important to mention that we don't know about the population standard deviation, so on this case we need to use the t distribution. Since our interval is at 90% of confidence, our significance level would be given by and
. The degrees of freedom are given by:
We can find the critical values in excel using the following formulas:
"=T.INV(0.05,16)" for
"=T.INV(1-0.05,16)" for
The critical value
3) Calculate the margin of error (m)
The margin of error for the sample mean is given by this formula:
4) Calculate the confidence interval
The interval for the mean is given by this formula:
And calculating the limits we got:
The 90% confidence interval is given by (17.332;21.068) and rounded would be: (17.3;21.1)
Part c
No, because 18 is above the lower limit of the confidence interval.
Part d
Because the parent population is assumed to be normally distributed.
The reason of this is because the t distribution is an special case of the normal distribution when the degrees of freedom increase.
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The events A and B are mutually exclusive. If P(A)=0.1 and P(B)=0.4, what is P(A or B)? ASAP
What does deleted account mean on a answered questionWaiting for answer on hraph
Answers
Answer:
-4
Step-by-step explanation:
If you multiply out the square, you can see ...
(x +p)^2 = q
x^2 +2px +p^2 = q
The coefficient of the x-term is 2p, so ...
2p = -8
p = -8/2 = -4
Answers
Answer:
a) 0 ≤ d ≤ 21 . . domain; 0 ≤ B ≤ 400 . . range
c) B(12) = 0
d) 4th segment
Step-by-step explanation:
(a) The domain of the function B(d) is from d = 0 to the number of days the account was open:
0 ≤ d ≤ 21 . . . . domain
The range is the set of values the bank balance might have. We know the minimum is 0 and the maximum is 400:
0 ≤ B ≤ 400 . . . . range
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(b) (missing question content)
__
(c) The balance on day 12 is B(12). We're told it is zero, so...
B(12) = 0
__
(d) The 4th segment of the graph is at B(d) = 0.
In this context, it is reasonable to assume the vertical scale starts at 0 at the horizontal axis. We are told that (12, 0) is a point on the graph. It is consistent with this assumption that slightly more than halfway through the graphed domain, the graph meets the horizontal axis. The graph stays at the horizontal axis for "segment 4."
Final answer:
The domain of the function is {1, 2, ..., 21}. The range of the function is {0, 100, 200, ..., 400}. In function notation, Ebony's bank balance reaching $0 on Day 12 would be written as f(12) = 0.
Explanation:
(a) The domain of the function represents the input values, which in this case are the number of days. Since Ebony kept her bank account open for 3 weeks, the domain would range from Day 1 to Day 21. So the domain is {1, 2, ..., 21}.
(b) The range of the function represents the output values, which in this case are the balances. Since Ebony's greatest balance during the 3 weeks was $400, the range would be {0, 100, 200, ..., 400}.
(c) To show that Ebony's bank balance first reached $0 on Day 12 using function notation, we would write it as f(12) = 0.
(d) The segment on the graph that represents Ebony's bank balance remaining at $0 from Day 12 through Day 15 would be Segment 4. This is because Segment 4 starts at the point where the balance is $0 on Day 12 and continues through Day 15 without any change in the balance.
Learn more about Bank account balance here:
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Answers
Answer:20-2=18
Step-by-step explanation: it is 18 because 20-2 is 18
If you take away 2 from 20 you are left with 18.
b) Response bias
c) Non-response bias
d) Selection bias
Answers
Answer: Selection bias
Step-by-step explanation:
From the question, we are informed that a travel agency contacted a department store and obtained the list of all people who made purchases using their credit cards at the store in the last month. The agency then surveyed a random sample from the list, calling them to ask their preference for air travel or train travel for taking holidays.
The bus depicted above is referred to as the selection bias. The selection bias is simply a bias that is introduced when the sample obtained is not a representation of the population that the researcher wants to analyze. Here, the study population doesn't represent the target population.
The list gotten was for the people who made purchases using their credit cards but the agency used the list to determine the preference for air travel or train travel for taking holidays. This shows selection bias.
Answers
Answer:
In a quadrilateral ABCD, ∠A = 100°, ∠B = 105° and ∠C = 70°, find ∠D.
Solution:
Here the sum of the four angles
or, ∠A + ∠B + ∠C + ∠D = 360°
We know, ∠A = 100°, ∠B = 105° and ∠C = 70°
or, 100° + 105° + 70° + ∠D = 360°
or, 275° + ∠D = 360°
∠D = 360° - 275°
Therefore, = 85°
i hope this was helpful. <3
crown?
Answers
When we solve the equation, we find that there are 26 seats in the theatre. Option C
How do we form and solve an equation from the given scenario?
We will consider the number of seats in the theatre as x.
The total cost of renting the theatre and the seats is $520 for the rental plus $30 × the number of seats should be expressed as 30x.
If every seat is sold, the total income from selling the tickets would be $50 × the number of seats is expressed as (50x)
The equation becomes
520 + 30x = 50x
520 = 50x - 30x
520 = 20x
x = 520/20
x = 26
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