I need assistance figuring this one out... I keep getting part B wrong. Thanks.

Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that the population of x values has an approximately normal distribution. 9.1 8.6 10.3 8.5 9.4 9.8 10.0 9.9 11.2 12.1 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean reading x and the sample standard deviation s. (in mg/dl; round your answers to two decimal places.) x = 9.89 mg/dl S = 1.12 mg/dl (b) Find a 99.9% confidence interval for the population mean of total calcium in this patient's blood. (in mg/dl; round your answer to two decimal places.) lower limit 8.72 X mg/dl upper limit 11.1 X mg/dl (c) Based on your results in part (b), do you think this patient still has a calcium deficiency? Explain. Yes. This confidence interval suggests that the patient may still have a calcium deficiency. Yes. This confidence interval suggests that the patient no longer has a calcium deficiency. O No. This confidence interval suggests that the patient may still have a calcium deficiency. O No. This confidence interval suggests that the patient no longer has a calcium deficiency