Problem Set 1
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School
California State University, Fullerton *
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Course
307
Subject
Communications
Date
Apr 3, 2024
Type
Pages
2
Uploaded by MegaIbexMaster156
Problem Set 1 – COMM 307 by Dr. Sunyoung Park
Copying & paste information from online sources is plagiarism which violates academic integrity.
All your answers should be in your own words.
Q1 – Q3 are based on the following (3 points per a question).
In 2010, on average, CSULB students spent 65 minutes per week on Netflix. We are
investigating whether the average number of minutes spent on Netflix by current CSULB
students differs from the 2010 average.
Q1. State a null hypothesis (H0)
-
There is no difference between the amount of time students spend on netflix during the
year of 2010 to now.
Q2. State an alternative hypothesis (H1; one-tailed test)
Average Netflix time consumption from students during the year of 2010 differs from time
consumption today.
-
Is the weekly average for Netflix use among current CSULB students larger than 65
minutes for the weekly average of students during 2010?
Q3. State an alternative hypothesis (H1; two-tailed test)
-
Time consumption spent on Netflix by CSULB students is not 65 minutes per week.
Q4. Provide a definition of p-value (3 pts).
-
The probability of observing a statistical measure as either extreme or as more extreme
than what is observed is known as the p-value.
Q5. Based on the lecture, what is the conventional level of significance (α)? (3 pts)
-
According to the lecture, the conventional level of significance is a threshold that holds
the probability of rejecting a null hypothesis by the test when the null is true. The level of
significance also holds a chance of making a type 1 error.
Q6. (True/False) When the null hypothesis is rejected, an alternative hypothesis is supported
(2pts). True
Q7. (True/False) When an observed p-value is higher than the level of significance (α), the null
hypothesis is rejected (2 pts). False
Q8. Explain similarities and differences between standard deviations and standard errors
(maximum 5 sentences; 3pts).
-
Both standard deviations and standard errors are both measures of variability. Standard
error, which represents the amount of random variation we would anticipate from
samples of the same size taken from the sample population, is the standard deviation of
the sampling distribution of a statistic. Standard errors are variability across samples,
whereas standard deviations are variability within a sample. While the standard errors
provide information on the shape of a hypothetical group of sample proportions or
means, the standard deviation of a sample provides information on the range of values
in the sample.
Q9. (True/False) Confidence interval allows us to know the exact value of the population mean
(2pts). False
Q10 – Q13 are based on the following (4 points per a question).
Dr. Park randomly sampled 200 CSULB undergrads and found the mean number of hours they
study is 15, with a standard deviation of 3. Dr. Park decides to calculate a 95% CI around the
statistic.
Show your calculation process in addition to the answers.
Q10. Find a standard error.
I have attached a file of my answers to question 10-14, it’s a scanned document.
Q11. Find a lower end of 95% CI.
Q12. Find an upper end of 95% CI.
Q13. Interpret the result of 95% CI in one or two sentences.
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