The owner of a speciality coffee shop wants to study coffee purchasing habits of customers at her shop. She selected a random sample of 60 customers during a certain week, with the following results: • The amount Spent was X ¯ = $ 7.25 , S = $1 .75 . • Thirty-one customers say they “definitely willâ€� recommend the specialty coffee shop to family and friends. a. At the 0.05 level of significance, is there evidence that the population mean amount spent was different from $ 6.50 ? b. Determine the p -value in (a). c. At the 0.05 level of significance, is there evidence that more than 50 % of all the customers say they “definitely willâ€� recommend the speciality coffee shop to family and friends? d. What is your answer to (a) if the sample mean equals $ 6.25 ? e. What is your answer to (c) if 398 customers say that “definitely willâ€� recommend the speciality coffee shop to family and friends?
The owner of a speciality coffee shop wants to study coffee purchasing habits of customers at her shop. She selected a random sample of 60 customers during a certain week, with the following results: • The amount Spent was X ¯ = $ 7.25 , S = $1 .75 . • Thirty-one customers say they “definitely willâ€� recommend the specialty coffee shop to family and friends. a. At the 0.05 level of significance, is there evidence that the population mean amount spent was different from $ 6.50 ? b. Determine the p -value in (a). c. At the 0.05 level of significance, is there evidence that more than 50 % of all the customers say they “definitely willâ€� recommend the speciality coffee shop to family and friends? d. What is your answer to (a) if the sample mean equals $ 6.25 ? e. What is your answer to (c) if 398 customers say that “definitely willâ€� recommend the speciality coffee shop to family and friends?
Solution Summary: The author explains how to determine whether the population mean amount spent is different from 6.50. The sample size is 60 and the level of significance is 0.05.
The owner of a speciality coffee shop wants to study coffee purchasing habits of customers at her shop. She selected a random sample of 60 customers during a certain week, with the following results:
•
The amount Spent was
X
¯
=
$
7.25
,
S
=
$1
.75
.
•
Thirty-one customers say they “definitely will� recommend the specialty coffee shop to family and friends.
a. At the 0.05 level of significance, is there evidence that the population mean amount spent was different from
$
6.50
?
b. Determine the p-value in (a).
c. At the 0.05 level of significance, is there evidence that more than
50
%
of all the customers say they “definitely will� recommend the speciality coffee shop to family and friends?
d. What is your answer to (a) if the sample mean equals
$
6.25
?
e. What is your answer to (c) if 398 customers say that “definitely will� recommend the speciality coffee shop to family and friends?
Definition Definition Number of subjects or observations included in a study. A large sample size typically provides more reliable results and better representation of the population. As sample size and width of confidence interval are inversely related, if the sample size is increased, the width of the confidence interval decreases.
2 (VaR and ES) Suppose X1
are independent. Prove that
~
Unif[-0.5, 0.5] and X2
VaRa (X1X2) < VaRa(X1) + VaRa (X2).
~
Unif[-0.5, 0.5]
8 (Correlation and Diversification)
Assume we have two stocks, A and B, show that a particular combination
of the two stocks produce a risk-free portfolio when the correlation between
the return of A and B is -1.
9 (Portfolio allocation)
Suppose R₁ and R2 are returns of 2 assets and with expected return and
variance respectively r₁ and 72 and variance-covariance σ2, 0%½ and σ12. Find
−∞ ≤ w ≤ ∞ such that the portfolio wR₁ + (1 - w) R₂ has the smallest
risk.
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Hypothesis Testing - Solving Problems With Proportions; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=76VruarGn2Q;License: Standard YouTube License, CC-BY
Hypothesis Testing and Confidence Intervals (FRM Part 1 – Book 2 – Chapter 5); Author: Analystprep;https://www.youtube.com/watch?v=vth3yZIUlGQ;License: Standard YouTube License, CC-BY