luppose that 14 children, who were learning to ride twowheel bikes, were surveyed to determine how long they had to use training wheels. It was revealed that they used them an average of nine nonths with a sample standard deviation of three months. Assume that the underlying population distribution is normal. El Part (a) (i) Enter an exact number as an integer, fraction, or decimal. } = (ii) Enter an exact number as an integer, fraction. or decimal. 8x: (iii) Enter an exact number as an integer, fraction, or decimal. (iv) Enter an exact number as an integer, fraction, or decimal. n - 1 = Which distribution should you use for this problem? (Enter your answer in the form 2 or tdfwhere df is the degrees of freedom.) E Explain your choice. 0 The Student's t-distribution for 13 degrees of freedom should be used because we do not know the population standard deviation. 0 The Student's t-distribution for 14 degrees of freedom should be used because the sample standard deviation is known. 0 The standard normal distribution should be used because the sample standard deviation is known. 0 The standard normal distribution should be used because the population standard deviation is known. Construct a 99% condence interval for the population mean length of time using training wheels. (i) State the condence interval. (Round your answers to two decimal places.) (ii) Sketch the graph. (Round your answers to two decimal places. Enter your (1/2 to three decimal places.) an: 1|:l |:l 9| (iii) Calculate the error bound. (Round your answer to two decimal places.)