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Guest
Guest
The time taken for grade 4 students to complete a small jigsaw puzzle follows a normal distribution with a standard deviation of 30 seconds. If 70% of grade 4 students complete the puzzle in 4 minutes or less, find the mean completion time for grade 4 students.
My working out:
s = 30
x - mean /s = z score
then were do I go from here?
My working out:
s = 30
x - mean /s = z score
then were do I go from here?