A random sample of 25 values is drawn from a mound-shaped and symmetric distribution. The sample mean is 12 and the sample standard deviation is 2. Use a level of significance of 0.05 to conduct a two-tailed test of the claim that the population mean is 11.5. 1. How many degrees of freedom do we use? 2. Compute the t value of the sample test statistic. (Round your answer to three decimal places.)

Need help on a and finding the t and p value

Consider the following data: −10, −10, 0, 3, −10, 3, 3  Step 1 of 3: Calculate the value of the sample Variance. Round your answer to one decimal place. Step 2 of 3: Calculate the value of the sample deviation. Round your answer to one decimal place. Step 3 of 3: Calculate the value of the range.

A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 129.5-cm and a standard deviation of 0.8-cm. For shipment, 27 steel rods are bundled together.Find P69, which is the average length separating the smallest 69% bundles from the largest 31% bundles.P69 = ________-cmEnter your answer as a number accurate to 2 decimal place. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately o = 22.3. You would like to be 98% confident that your estimate is within 3 of the true population mean. How large of a sample size is required? Do not round mid-calculation. n =