Question 7 1 pts A researcher investigated four different word lists for use in hearing assessments. She wanted to know whether the lists were equally difficult to understand in the presence of a noisy background. To find out, she tested 96 subjects with normal hearing. She randomly assigned 24 to each of the four word lists and measured the number of words perceived correctly in the presence of background noise. Here are the summary statistics for number of words perceived correctly for each of the four words lists. Word List A Word List B Word List C Word List D Sample size 24 24 24 24 Sample mean 32.5 34.0 25.75 26.25 Sample standard 5.1 7.1 6.3 deviation 6.7 Calculate the pooled sample standard deviation. Round to two decimal places.Question 8 0.5 pts A researcher investigated four different word lists for use in hearing assessments. She wanted to know whether the lists were equally difficult to understand in the presence of a noisy background. To nd out, she tested 96 subjects with normal hearing. She randomly assigned 24 to each of the four word lists and measured the number of words perceived correctly in the presence of background noise. Here are the summary statistics for number of words perceived correctly for each of the four words lists. Word List A Word List B Word List C. Word Ust D Sample size 24 24 24 24 Sample mean 32.5 34.0 25.75 26.25 :Zzroitandm 5.1 7.1 6.3 6.7 Suppose an F-test is to be performed. Which of the following is the correct null hypothesis? 0 None of the explanatory variables help to predict the number of words perceived correctly. 0 At least one of the explanatory variables helps to predict the number of words perceived correctly. 0 All of the word lists have the same mean number of words perceived correctly. 0 At least one of the word lists has a different mean number ofwords perceived correctly. 0 All of the word lists have a different mean number ofwords perceived correctly. Question 9 1 pts A researcher investigated four different word lists for use in hearing assessments. She wanted to know whether the lists were equally difcult to understand in the presence of a noisy background. To nd out, she tested 96 subjects with normal hearing. She randomly assigned 24 to each of the four word lists and measured the number of words perceived correctly in the presence of background noise. Here are the summary statistics for number of words perceived correctly for each of the four words lists. Word List A Sample size 24 Sample mean 32.5 Sample standard 5.1 deviation Suppose an F-statistic was calculated. - numerator df = - denominator df = Word List B Word List C. Ward list D 24 24 24 34.0 25.75 26.25 7.1 6.3 6.7 How many degrees of freedom does the F-statistic have