We Are Social and Hootsuite reported that the typical American spends 2.02 hours (121 minutes) per day accessing the internet via mobile devices. In order to test the validity of this statement, you select a sample of 30 friends and family. The results for the time spent per day accessing the internet via mobile devices (in minutes) are stored in InternetMobileTime. a. Is there evidence that the population mean time spent per day accessing the internet via mobile devices is different from 121 minutes? Use the p -value approach and a level of significance of 0.05. b. What assumption about the population distribution is needed in order to conduct the t test in (a)? c. Make a list of the various ways you could evaluate the assumption noted in (b). d. Evaluate the assumption noted in (b) and determine whether the test in (a) is valid.
We Are Social and Hootsuite reported that the typical American spends 2.02 hours (121 minutes) per day accessing the internet via mobile devices. In order to test the validity of this statement, you select a sample of 30 friends and family. The results for the time spent per day accessing the internet via mobile devices (in minutes) are stored in InternetMobileTime. a. Is there evidence that the population mean time spent per day accessing the internet via mobile devices is different from 121 minutes? Use the p -value approach and a level of significance of 0.05. b. What assumption about the population distribution is needed in order to conduct the t test in (a)? c. Make a list of the various ways you could evaluate the assumption noted in (b). d. Evaluate the assumption noted in (b) and determine whether the test in (a) is valid.
Solution Summary: The author explains how to perform the t-test using Minitab.
We Are Social and Hootsuite reported that the typical American spends 2.02 hours (121 minutes) per day accessing the internet via mobile devices.
In order to test the validity of this statement, you select a sample of 30 friends and family. The results for the time spent per day accessing the internet via mobile devices (in minutes) are stored in InternetMobileTime.
a. Is there evidence that the population mean time spent per day accessing the internet via mobile devices is different from 121 minutes? Use the p-value approach and a level of significance of 0.05.
b. What assumption about the population distribution is needed in order to conduct the t test in (a)?
c. Make a list of the various ways you could evaluate the assumption noted in (b).
d. Evaluate the assumption noted in (b) and determine whether the test in (a) is valid.
Statistics that help describe, summarize, and present information extracted from data. Descriptive statistics include concepts related to measures of central tendency, measures of variability, measures of frequency, shape of distribution, and some data visualization techniques/tools such as pivot tables, charts, and graphs.
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.
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