Answer:
UCL (x bar) = 424
LCL (x bar) = 376
Explanation:
Given:
Average calories contained, μ = 400
Standard deviation, σ = 30 calories
Sample size, n = 25
a) UCL (x bar) =
On substituting the respective values, we get
UCL (x bar) =

or
UCL (x bar) = 424
Similarly,
LCL (x bar) =
On substituting the respective values, we get
LCL (x bar) =

or
LCL (x bar) = 376