Answer:
a. 5 out of 21
b. (4.1811, 5.3589)
Step-by-step explanation:
a. We can see from the stem plot that 5 out of the 21 tunas have dangerous levels of copper in their system because the copper level reached over 5.7, and the problem states "Dangerous levels of copper are classified when they reach beyond 5.7 parts per million"
b. How to find it on calculator
Step 1: [stat]
Step 2: go to [tests]
Step 3: go down to [7: zinterval]
Step 4: make sure input is on [stats]
Step 5: input the following
: 1.16
X (with the line above it): 4.77
n: 21
c-level: .98