PT United Tractor Tbkis the largest distributor of heavy equipment in Indonesia. Their daily production follows a normal probability distribution with a population mean of 200 and a population standard deviation of 16. Recently, because the price of minerals product is getting higher due to Russia and Ukraine conflict, the demand for heavy equipment has also increased. Therefore, Edhie Sarwono, the CEO, decided to implement a new production method. He would like to investigate whether there has been an increase in the weekly production. Suppose, as production manager, you are assigned to do this task. From a random sample of 30 production days, the mean is found to be 205.3. In order to provide information for the CEO, you need to do several tasks below. a. Develop hypotheses to test whether there is an increase in production rate. b. Calculate the test statistics. c. Find the p-value and critical value from the table at 95% confidence level. d. Test the hypothesis using p-value approach and critical value approach. e. What conclusion can you give to the CEO?

Abbi is a final year student in OxfordUniversity doing her dissertation. After discussing with her supervisor, her research objective is to estimate the relationship between returns of stocks and level of risk of stocks (i.e. standard deviation of stock returns). Abbi is using primary data and secondary data for her research. a). List 3 main sources to collect primary data and secondary data, respectively; b) Abbi collected the below data from Thomson Reuters Eikon of Tesco. How much is Arithmetic mean of the stock price? The median of the stock price? The monthly percentage change on 01/04/2020? Date Tesco Stock Price 01/05/2019 220.0 01/06/2019 224.1 01/07/2019 220.7 01/08/2019 216.6 01/09/2019 238.2 01/10/2019 232.5 01/11/2019 229.4 01/12/2019 255.2 01/01/2020 246.9 01/02/2020 228.5 01/03/2020 228.8 01/04/2020 218.8 03/04/2020 223.9 c). What is the best type of chart to represent the variable…

The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1775 pounds and a standard deviation of 70 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, u, of the cables is now greater than 1775 pounds. To see if this is the case, 14 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1812 pounds. Assume that the population is normally distributed. Can we support, at the 0.10 level of significance, the claim that the population mean breaking strength of the newly- manufactured cables is greater than 1775 pounds? Assume that the population standard deviation has not changed. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the…

An energy study found that household use of electricity had a mean of 682 and a standard deviation of 551 ​kilowatt-hours.    Suppose the distribution of energy use was normal. Using a​ table, calculator, or software that can give normal​ probabilities, find the proportion of households with electricity use greater than 1000 ​kilowatt-hours.