9. (1+1+1+1= 4 marks) The results from monitoring chloride levels (in mg/L) in underground water during 7-day period was obtained by a researcher. The researcher calculated the sample mean and sample standard deviation. He obtained the value of x=26 mg/L for the sample mean and the value of s = 5 mg/L for sample standard deviation. Sample size n = 7 Is it sufficient sample evidence to conclude that the mean chloride level in underground water is less than 32 mg/L? Test appropriate hypotheses at = 0.05 using critical value approach. Assume that chloride levels in underground water is normal. State null and research hypotheses: a. Ho H: b. Find the observed value of test statistic. Keep 3 digits after decimal point in the expression for observed value of test statistics. The observed value of test statistic is t obs. c. State the rejection region (in the form of inequality). The rejection region is d. Decide whether null hypothesis is rejected or is not rejected at = 0.05, and insert the word rejected or the words not rejected into the following statement. Null hypothesis is at = 0.05. Insert the word sufficient or insufficient into the following statement. There is _sample evidence to conclude that the mean chloride level in underground water is less than 32 mg/L