EMPIRE™ Turf

EMPIRE™ Turf Research

Statistical significance in mowing rates difference

The following tests show the statistical significance in the difference in the mowing rates, and have been derived from a market research program.

The purpose of the research was to test the theory that there were differences in the mowing rates for Kikuyu & Couch compared to Empire Turf.

The following tests prove that there is a significant difference in mowing rates for the three different varieties.

  • TEST 1
    Kikuyu compared to EMPIRE™ Turf - fertilised twice per year
  • TEST 2
    Couch compared to EMPIRE™ Turf - fertilised twice per year
  • TEST 3
    Kikuyu compared to EMPIRE™ Turf - fertilised once per year
  • TEST 4
    Couch compared to EMPIRE™ Turf - fertilised once per year
  • TEST 5
    Kikuyu compared to EMPIRE™ Turf - under moderate wearing conditions

The purpose of a means test is to compare the size of the difference between two means in relation to the amount of inherent variability (the random error) in the data. If the random error is large then we are unlikely to find a significant difference between means unless this difference is also very large.

The paired T tests use standard deviation and the mean (or average) for the mowing rates to compare the difference in mowing.

 


 

TEST 1

Kikuyu compared to EMPIRE™ Turf - fertilised twice per year

To test whether there was a difference in the mowing rate of EMPIRE™ and Kikuyu when fertilised twice per year, the following paired samples test was conducted.

Ho: µ diff = 0 or in other words no difference
H1: µ diff > 0 or < 0 or is there a significant difference

Reject Ho if sig value < 0.05

Since 0.03 < 0.05 we reject Ho and conclude there is a significant difference in the mean mowing rates for EMPIRE™ and Kikuyu, at the 95% confidence level.


Paired Samples Statistics
  Mean No. Std. Deviation Std. Error Mean
Pair 1 EMPIRE2 21.2333 30 6.5637 1.1984
  KIKUYU2 48.9333 30 7.5014 1.3696

 

Paired Samples Correlations
  No. Correlation Sig
Pair 1 EMPIRE2
&
KIKUYU2
30 0.528 0.003

 

Paired Samples Test
  Paired Differences  
  Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
  Lower
Pair 1 EMPIRE2
&
KIKUYU2
-27.7000 6.8840 1.2568 -30.2705
 
  Sig. (2-tailed)
    t d  
  Upper  
Pair 1 EMPIRE2
&
KIKUYU2
-25.1295 -22.039 29 0.000

Conclusion: There is a significant difference between the mowing rates, thus with EMPIRE™ Turf you can save yourself a lot of money and time by not having to mow your lawn as regularly.

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TEST 2

Couch compared to EMPIRE™ Turf - fertilised twice per year

To test whether there was a significant difference in the mean mowing rates for EMPIRE™ and Couch grass when fertilised twice per year, the following paired samples test was conducted.

Ho: µ diff= 0 or in other words no difference
H1: µ diff > 0 or < 0 or is there a significant difference

Reject Ho if sig value < 0.05

Since 0.256 < 0.05 we accept Ho and conclude there is no significant difference in the mean mowing rates for EMPIRE™ and Couch.


Paired Samples Statistics
  Mean No. Std. Deviation Std. Error Mean
Pair 1 EMPIRE2 21.2333 30 6.5637 1.1984
  COUCH2 37.8667 30 7.9989 1.4604

 

Paired Samples Correlations
  No. Correlation Sig
Pair 1 EMPIRE2
&
COUCH2
30 0.214 0.256

 

Paired Samples Test
  Paired Differences  
  Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
  Lower
Pair 1 EMPIRE2
&
COUCH2
-16.6333 9.1970 1.6791 -20.0676
 
  Sig. (2-tailed)
    t d  
  Upper  
Pair 1 EMPIRE2
&
COUCH2
-13.1991 -9.908 29 0.000

Conclusion: There is no significant difference in the mowing rates of Couch and EMPIRE™ at the 95% confidence level.

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TEST 3

Kikuyu compared to EMPIRE™ Turf - fertilised once per year

One of our aims was to research the difference in mowing rates for EMPIRE™ compared to other grasses when only fertilised once per year. The reason for this is that EMPIRE™ Turf has a distinct advantage as it will still look great even if it is only fertilised once per year, whilst other grasses may thin out. The mowing rates of turf when fertilised only once per year was also of interest.

To test whether there was a difference in the mowing rate of EMPIRE™ and Kikuyu when fertilised once per year, the following paired samples test was conducted.

Ho: µ diff= 0 or in other words no difference
H1: µ diff > 0 or < 0 or is there a significant difference

Reject Ho if sig value < 0.05

Since 0.04 < 0.05 we reject Ho and conclude there is a significant difference in the mean mowing rates for EMPIRE™ and Kikuyu, when fertilised once per year.


Paired Samples Statistics
  Mean No. Std. Deviation Std. Error Mean
Pair 1 EMPIRE2 16.7000 30 5.7304 1.0462
  KIKUYU2 39.5000 30 7.8466 1.4326

 

Paired Samples Correlations
  No. Correlation Sig
Pair 1 EMPIRE2
&
KIKUYU2
30 0.507 0.004

 

Paired Samples Test
  Paired Differences  
  Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
  Lower
Pair 1 EMPIRE2
&
KIKUYU2
-22.8000 6.9847 1.2752 -25.4081
 
  Sig. (2-tailed)
    t d  
  Upper  
Pair 1 EMPIRE2
&
KIKUYU2
-20.1919 -17.879 29 0.000

Conclusion: Since 0.04 < 0.05 we reject Ho and conclude there is a significant difference in the mean mowing rates for EMPIRE™ and Kikuyu, when fertilised once per year.

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TEST 4

Couch compared to EMPIRE™ Turf - fertilised once per year

To test whether there was a significant difference in the mean mowing rates for EMPIRE™ Turf and Couch when fertilised once per year, the following paired samples test was conducted.

Ho: µ diff= 0 or in other words no difference
H1: µ diff > 0 or < 0 or is there a significant difference

Reject Ho if sig value < 0.05

Since 0.381 < 0.05 we accept Ho and conclude there is no significant difference in the mean mowing rates for EMPIRE™ and Couch.


Paired Samples Statistics
  Mean No. Std. Deviation Std. Error Mean
Pair 1 EMPIRE2 16.7000 30 5.7304 1.0462
  COUCH2 31.9000 30 8.4582 1.5443

 

Paired Samples Correlations
  No. Correlation Sig
Pair 1 EMPIRE2
&
COUCH2
30 0.166 0.381

 

Paired Samples Test
  Paired Differences  
  Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
  Lower
Pair 1 EMPIRE2
&
COUCH2
-15.2000 9.3970 1.7156 -18.7089
 
  Sig. (2-tailed)
    t d  
  Upper  
Pair 1 EMPIRE2
&
COUCH2
-11.6911 -8.860 29 0.000

Conclusion: There is no significant difference at the 95% confidence interval for EMPIRE™ Turf and Couch.

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TEST 5

Kikuyu compared to EMPIRE™ Turf - under moderate wearing conditions

The final test that we wanted was to compare EMPIRE™ Turf to Kikuyu under moderate wearing conditions. It is recommended that Kikuyu needs fertilizing twice per year, whilst EMPIRE™ only requires fertilising once per year. Part of this included comparing the mowing rates in moderate wearing areas.

Ho: µ diff= 0 or in other words no difference
H1: µ diff > 0 or < 0 or is there a significant difference

Reject Ho if sig value < 0.05

Since 0.000 < 0.05 we reject Ho and conclude that there is a significant deifference in the mowing rates of EMPIRE™ Turf and Kikuyu.


Paired Samples Statistics
  Mean No. Std. Deviation Std. Error Mean
Pair 1 EMPIRE2 16.7000 30 5.7304 1.0462
  KIKUYU2 48.9333 30 7.5014 1.3696

 

Paired Samples Correlations
  No. Correlation Sig
Pair 1 EMPIRE2
&
KIKUYU2
30 0.767 0.000

 

Paired Samples Test
  Paired Differences  
  Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference
  Lower
Pair 1 EMPIRE2
&
KIKUYU2
-32.2333 4.8115 0.8785 -30.4367
 
  Sig. (2-tailed)
    t d  
  Upper  
Pair 1 EMPIRE2
&
KIKUYU2
-34.0300 36.693 29 0.000

Conclusion: There is a significant difference in the mowing rates of EMPIRE™ Turf compared to Kikuyu under moderate wearing conditions. Thus if you want to save yourself time and money purchase some EMPIRE™ turf and enjoy the difference.

 

"EMPIRE™ ZOYSIA – It just keeps looking good"