Question

INFERENCES ABOUT THE DIFFERENCES

ENGINEERS IN A LARGE CORPORATION ARE CONCERNED ABOUT THE BONUS AMOUNT CLAIMING THAT THE AMOUNDS DECREASED COMPARED TO THE PREVIOUS YEAR. A SAMPLE OF n = 9 ENGINEERS WAS SELECTED AT RANDOM AND THEIR BONUS AMOUNTS FOR TWO LAST YEARS (2015 AND 2016) WERE SUMMARIZED. THE SUMMARIES SHOW THAT: (X-BAR) = (SAMPLE MEAN FOR 2015) = 4,880 (Y-BAR) = (SAMPLE MEAN FOR 2016) = 4,140 AND S = (SAMPLE SD FOR DIFFERENCES) = 1,200

1. (A) AT THE 5% SIGNIFICANCE LEVEL, DO ENGINEERS HAVE SUFFICIENT EVIDENCE THAT THE POPULATION AVERAGE BONUS IN 2016 WAS LOWER THAN IN 2015?

   CIRCLE ONE: YES or NO

   SHOW ALL ITEMS NEEDED FOR HYPOTHESIS TESTING (LISTED BELOW)

   NULL HYPOTHESIS STATES:
   ALTERNATIVE HYPOTHESIS STATES:
   TEST STATISTIC =
   CRITICAL VALUE =
   REJECTION RULE STATES:
   DECISION –

2. (B) ESTIMATE THE POPULATION AVERAGE CHANGE IN BONUS AMOUNT WITH THE 95% CONFIDENCE. SHOW THE DETAILED ANSWERS, PLEASE.

CRITICAL VALUE =

MID-POINT =

MARGIN OF ERROR =

UPPER CONFIDENCE LIMIT =

LOWER CONFIDENCE LIMIT =

Answer 1