I really need help understanding how to work through these 2 homework questions, could someone please help me understand. Thanks.

According to a report, the standard deviation of monthly cell phone bills was $49.97 three years ago. A researcher suspects that the standard deviation of monthly cell phone bills is different from today. (a) Determine the null and alternative hypotheses. (b) Explain what it would mean to make a Type I error. (c) Explain what it would mean to make a Type II error. (a) State the hypotheses. Ho: Hy : (Type integers or decimals. Do not round.) (b) Explain what it would mean to make a Type I error. Choose the correct answer below. A. The sample evidence did not lead the researcher to believe the standard deviation of the monthly cell phone bill is higher than $49.97, when in fact the standard deviation of the bill is higher than $49.97. O B. The sample evidence did not lead the researcher to believe the standard deviation of the monthly cell phone bill is different from $49.97, when in fact the standard deviation of the bill is different from $49.97. O C. The sample evidence led the researcher to believe the standard deviation of the monthly cell phone bill is higher than $49.97, when in fact the standard deviation of the bill is $49.97. O D. The sample evidence led the researcher to believe the standard deviation of the monthly cell phone bill is different from $49.97, when in fact the standard deviation of the bill is $49.97. (c) Explain what it would mean to make a Type II error. Choose the correct answer below. O A. The sample evidence did not lead the researcher to believe the standard deviation of the monthly cell phone bill is different from $49.97, when in fact the standard deviation of the bill is different from $49.97. O B. The sample evidence led the researcher to believe the standard deviation of the monthly cell phone bill is different from $49.97, when in fact the standard deviation of the bill is different from $49.97. O C. The sample evidence did not lead the researcher to believe the standard deviation of the monthly cell phone bill is higher than $49.97, when in fact the standard deviation of the bill is higher than $49.97. O D. The sample evidence led the researcher to believe the standard deviation of the monthly cell phone bill is different from $49.97, when in fact the standard deviation of the bill is $49.97.The average daily volume of a computer stock in 2011 was u = 35.1 million shares, according to a reliable source. A stock analyst believes that the stock volume in 2014 is different from the 2011 level. Based on a random sample of 30 trading days in 2014, he finds the sample mean to be 28.4 million shares, with a standard deviation of s = 11.3 million shares. Test the hypotheses by constructing a 95% confidence interval. Complete parts (a) through (c) below. (a) State the hypotheses for the test. Ho |35.1 million shares |35.1 million shares (b) Construct a 95% confidence interval about the sample mean of stocks traded in 2014. The lower bound is million shares. The upper bound is million shares. (Round to three decimal places as needed.) (c) Will the researcher reject the null hypothesis? O A. Do not reject the null hypothesis because u = 35.1 million shares does not fall in the confidence interval. O B. Reject the null hypothesis because u = 35.1 million shares falls in the confidence interval. O C. Reject the null hypothesis because u = 35.1 million shares does not fall in the confidence interval. O D. Do not reject the null hypothesis because u = 35.1 million shares falls in the confidence interval