MS 150 Statistic Quiz 7 Spring 2002 8.1

In the soy sauce survey the volumes of 37 bottles of soy sauce were recorded. The mean volume is 889 milliliters with a sample standard deviation of 590 milliliters. Construct a 95% confidence interval for the population mean volume for soy sauce based on this data.

  1. ________ What is z-critical?
  2. ________ What is the error E?
  3. The confidence interval for the population mean is: _______ < < _______
Statistic or Parameter Symbol Equations Excel
Normal Statistics
Calculate a z value from an x z = standardize.gif (905 bytes) =STANDARDIZE(x, , s)
Calculate an x value from a z x = s z + =s*z+
Calculate a z-statistic from an x z xbartoz.gif (1022 bytes) =(x - )/(sx/SQRT(n))
Calculate a t-statistic (t-stat) t xbartot.gif (1028 bytes) =(x - )/(sx/SQRT(n))
Calculate an x from a z   xbarfromz.gif (1060 bytes) = + zc*sx/sqrt(n)
Find a probability p from a z value     =NORMSDIST(z)
Find a z value from a probability p     =NORMSINV(p)
Confidence interval statistics
Degrees of freedom df = n-1 =COUNT(data)-1
Find a zc value from a confidence level c zc   =ABS(NORMSINV((1-c)/2))
Find a tc value from a confidence level c tc   =TINV(1-c,df)
Calculate an error tolerance E of a mean for n >= 30 using sx E error_tolerance_zc.gif (989 bytes) =zc*sx/SQRT(n)
Calculate an error tolerance E of a mean for n < 30 using sx. Can also be used for n >= 30. E error_tolerance_tc.gif (989 bytes) =tc*sx/SQRT(n)
Calculate a confidence interval for a population mean from a sample mean x and an error tolerance E   x-E<= <=x+E  

 


 

StoreBrandPriceVolume/ml
Ace CommYamasa0.55150
Ace CommYamasa1.6500
Ace CommYamasa3.951000
Ace CommYamasa5.951800
AmbrosKikkoman1.65600
AmbrosKikkoman3.851000
Bamboo InnYamasa1.85500
Best BuyKikkoman1.10148
Best BuyKikkoman2.03296
Best BuyKikkoman3.13591
Best BuyKikkoman5.541890
En's 7 StarKikkoman1.25148
En's 7 StarYamasa2.1500
En's 7 StarYamasa4.951000
En's 7 StarYamasa6.251800
JosaiahKikkoman3.91000
JosaiahYamasa1.9500
NakasoneKikkoman2.25500
NakasoneKikkoman3.971000
NakasoneKikkoman3.971000
NakasoneKikkoman4.691800
Palm TerraceKikkoman1.15148
Palm TerraceKikkoman1.29296
Palm TerraceKikkoman2.48591
Palm TerraceKikkoman4.281200
Palm TerraceKikkoman6.281890
PanueloKikkoman1.45148
PanueloKikkoman2.96296
PanueloYamasa1.95500
PanueloYamasa4.751000
PanueloYamasa5.151800
Wall MartKikkoman1.85600
Wall MartKikkoman5.401600
Wall MartYamasa5.41800
YoshieKikkoman1.90500
YoshieKikkoman3.401000
YoshieKikkoman5.501800